"He was afraid we'd get hurt," sniffed Bob.

"Karl likes you," said his father. "He doesn't want anything to happen to you."

"We can take care of ourselves."

"I know that," his father assented. "Do you want to go very much?"

"We certainly do," cried Bob and Hugh in one breath.

"Well," said Mr. Cook, "I'm proud of you for wanting to help, and under the circumstances I don't see how I can refuse."

"That's great!" cried Bob enthusiastically.

"It won't all be fun by a good deal," his father warned him.

"We know that, but we're ready to do anything that comes along."

The two boys were much excited at the prospect of the guard duty. It seemed to them that at last they had been recognized as capable of aiding in the defense of their country. Perhaps if they had known what awaited them they would not have been quite so enthusiastic.



CHAPTER XX

ANOTHER SUSPECT

Hugh was going home for dinner, and was to return shortly afterward to accompany Bob and his father to the factory. He left the house and Bob started upstairs to prepare himself for the evening meal. On the landing of the stairs he heard some one talking over the telephone and stopped to listen. Of late he had become suspicious of every one and had fallen into the habit of noticing every little thing that happened.

It was the cook's voice and he was doubly interested at once.

"Yes," he heard her say, "this is Lena."

Bob flattened himself against the wall and listened intently.

"What's that?" Lena demanded over the 'phone. "In the hospital, you say!"

There was a pause while the other person talked to her.

"I will try to be there," said Lena. "I also have a message for you, but I don't know whether I should say it now or not; those blamed detectives are on to us."

There ensued another pause while Bob became more and more excited. What was this plot anyway that turned old and trusted servants against their masters? Was no one to be relied upon? Who could be trusted?

"Yes, I will tell Heinrich," said Lena speaking again. "Good-by."

She hung up the receiver and Bob continued up the stairs, whistling and trying to act as if he had heard nothing. He met Lena in the hall and she eyed him narrowly.

"Hello, Lena," he exclaimed cheerfully. "Fine day, isn't it?"

"Yes, Mr. Bob," she said, and passed on toward the back stairs.

No sooner was she gone than Bob turned and sped down stairs again to the library. He burst into the room breathlessly, causing his father, who was reading his evening paper to glance up in surprise.

"Father," exclaimed Bob in a tense whisper, "Lena's in it too."

"What's that?" demanded his father. "Sit down, Bob."

Bob grasped a chair and sat down facing his father. "Lena's in it too," he repeated.

"In what?"

"In the plot with Mr. Wernberg."

Mr. Cook laid down his paper. "Tell me what you know," he said soberly.

Bob repeated the part of Lena's telephone conversation that he had heard. "You see," he exclaimed, "she spoke about the hospital and that must have meant Mr. Wernberg; then she said the detectives were on to them; finally she said she'd tell Heinrich and also try to be there to-night."

"You don't know what she is to tell Heinrich and where she is to be to-night?"

"No, sir," said Bob. "That's all I heard."

"Well," exclaimed Mr. Cook after a moment's pause. "This is a nice state of affairs."

"What are you going to do about it?" asked Bob. "Are you still going to wait until to-morrow before you report Heinie to the police?"

Mr. Cook passed his hand across his brow as if to wipe away the doubts that assailed him. "Heinrich and Lena both," he muttered. "What a pity."

"I tell you what I'll do," he exclaimed finally. "I'll take Heinrich along with me to-night just as I planned, and I'll tell your mother under no conditions to let Lena go out this evening. In the morning we may know better what to do."

"I have a better scheme than that," said Bob eagerly.

"Tell me what it is."

"Take Heinrich along with you and watch him all the time; that part is all right. But let Lena go out if she wants to."

"What's the point of that?" demanded his father. "For all we know Lena may he able to do more harm than Heinrich; certainly she's smarter."

"Let her go out," said Bob, "and I'll go with her."

"I don't see what you mean."

"I'll follow her."

"You'd have to be disguised."

"I know it; I'll attend to that though."

"It might lead you to some very dangerous spot," said Mr. Cook. "I hate to have you do it."

"Look here, father," exclaimed Bob earnestly. "We're at war with Germany, aren't we? Well, just think of all those millions of men over in Europe on the battlefields; all the English and French, and Italians, and Belgians, and Russians, and all the others. If the United States is in the war we ought to be willing to do our part. Our allies in Europe are fighting for us as much as for themselves, and it seems to me that to disguise myself and follow the cook is a small thing for me to contribute to the common cause."

"I guess you're right, Bob," said his father.

"Why look here," continued Bob. "Just think of the way those men over there are every one of them risking their lives a hundred times a day. We just can't sit still and let them do all our fighting for us. We can give them money and food and I think we ought to expect to give our lives too if it is necessary. I know I don't want to hide behind somebody else and let him fight for me."

"You're all right, my boy," exclaimed Mr. Cook, rising to his feet. He grasped his son affectionately by the arm, and there were tears in his eyes as he did so. "You're all right," he repeated, "and I'm proud of you. You've got the spirit that every true American should have, and which I believe they do have. When Germany finds herself facing a million American troops and sees the Stars and Stripes floating from the opposing trenches she'll know she's beaten. I hope we'll show them that we mean business and the sooner we do, the quicker the war will be over."

"What kind of a disguise can I wear?" asked Bob.

"I guess you won't need a very elaborate one. Isn't there a false-face in the house with whiskers or a mustache on it!"

"I think there is one I used last hallowe'en."

"Get that then," said his father. "We can rip off the whiskers and glue them on your face. Put on an old suit of clothes and a sweater; wear a slouch hat and take along that hickory cane that I have. That ought to fix you up all right."

"I guess it will," exclaimed Bob, much excited at the prospect. "I'll go upstairs and look for the false-face now."

"Don't put it on until after dinner."

"I won't," said Bob as he hurried up to the attic in search of the disguise he was to wear. In a cupboard on the top floor he found the false-face and quickly tore the whiskers and mustache from it. He brought the handful of hair down to his room and hid it in his closet. He selected the oldest suit he owned and placed it on a chair with an old slouch hat he used to wear when he went fishing.

The announcement that dinner was ready put an end to any further preparations for the time being. The meal was a quiet one and there was but little conversation. Mrs. Cook's thoughts were of Harold and she was greatly worried about him; particularly as she did not know where his regiment had been sent. Mr. Cook, although he too was concerned about his elder son, was occupied principally with anxiety as to the plots that seemed to be brewing all about him, and the possible damage to his factory. Bob, needless to say, was highly excited over the prospects of adventure that the evening held forth for him.

Finally dinner was over. Mr. Cook dispatched Bob to the garage with a message to Heinrich to have the car ready in half an hour. As Bob ran across the lawn he met Lena returning from the garage. "Aha," he thought as he greeted her, "you saw Heinrich all right, didn't you?" He was fully convinced now that their cook and chauffeur were agents of Mr. Wernberg, and partners in crime. A moment later he reached the garage.

"Father wants you to bring the car around in half an hour," he announced to Heinrich, who was engaged in putting on a clean collar and necktie.

"What!" exclaimed Heinrich angrily. Bob had never before seen their chauffeur question any order that his father had given. "I can't."

"Those are his orders," said Bob, eyeing Heinrich closely.

"Does he want me to drive him out?"

"He does."

"But I can't," cried Heinrich. "I can't, I tell you; I have an appointment."

"I guess you'll have to break it then," was Bob's retort.

Heinrich wrung his hands in desperation. "What shall I do?" he moaned. "What shall I do?"

"Can't you change your appointment?"

"I do not think so," wailed Heinrich. "This iss terrible. Do you think your father would change his mind if I should speak to him?"

"I'm sure he wouldn't," said Bob. "I know he wants the car and he wants you to drive it. I heard him say that positively."

"This iss terrible," repeated Heinrich. "What will they do mitout me?"

"Who?"

"My friends."

"It's too bad," said Bob, more convinced every moment that mischief was afoot that evening. "I don't know what you can do about it though."

"Of course I have to go mit your father," said Heinrich finally, heaving a great sigh. "I wonder if he will want the car for long."

"I think he will."

"Very well," said Heinrich, becoming resigned to his fate, "I will be there but only because I do not wish to lose my job. But I fear something will happen."

"That's just what we want to prevent," thought Bob grimly. "All right then, Heinie," he said aloud. "Father will expect you in half an hour."

He hurried back to the house, warned his father that he should keep Heinrich always within sight, and related his conversation with the chauffeur as an argument for this course. Then he went upstairs, two steps at a time to make ready his disguise. While he was there Hugh arrived and went up to Bob's room.

"What are you doing, Bob?" he demanded.

"Putting on a disguise."

"What for?"

Bob told him.

"I want to go with you," exclaimed Hugh eagerly. "Two would be better than one anyway."

"Where are you going to get a disguise?"

"I'll borrow part of yours. You can certainly spare enough of those whiskers to make me a mustache anyway."

"You ought to have another hat."

"You can lend me an old cap, can't you? I've got on the oldest suit I own."

Bob brought out the glue pot and with Hugh's assistance was soon adorned with a set of black whiskers and a mustache. His hair did not match at all, but as he expected to wear a hat pulled far down over his eyes that fact did not make much difference. He put on the hat, and wearing his old clothes and a sweater looked at himself in the mirror.

"Whew," he exclaimed, "I'm certainly a hard looking character."

"You certainly are," agreed Hugh, "and you look about forty years old."

"All the better," said Bob. "Now let's get you fixed up."

With what was left of Bob's whiskers a small black mustache was twisted into shape and glued to Hugh's upper lip. It was remarkable to see what a great change in his appearance it made.

"When we take these things off, all the skin on our faces will come too," said Hugh inspecting himself in the mirror.

"Don't you care," exclaimed Bob. "What we're interested in at present is to have them stay on to-night. How about a hat for you now?" He rummaged around on the closet shelf and produced an old cap and a derby.

"Put the derby on, Hugh," he urged. "You'll look just like Charlie Chaplin."

"That wouldn't do, I'm afraid," laughed Hugh. "I'd have too big a crowd following me."

"Turn up the ends of your mustache and you'll look like the kaiser."

"Not for me!" exclaimed Hugh hastily. "I don't want to look like anything German. I'll wear the cap, I guess. I think that's better than the derby."

At that moment Mr. Cook appeared upon the scene. He stood and looked at the two boys approvingly. "Well," he said, "you certainly look like a couple of tough customers all right. I'm glad you're going along, Hugh; I think two will be better than one."

"Is Lena still here?" asked Bob.

"Still here," said his father. "She's getting ready to leave though and you two had better be prepared."

"Where's Heinrich?"

"He's due in about five minutes."

"You'd better watch him, father," warned Bob.

"Don't worry about that," said Mr. Cook soberly. "I suppose that you two 'things' will come to the factory later. I expect to be there all night."

"We'll try to get there," said Bob. "We'll keep track of Lena as long as we can, and if it's possible we'll report to you at the office."

"Good," exclaimed Mr. Cook. "Don't forget to be very careful, and don't get into trouble if you can help it."

"We'll do our best," Bob promised.



CHAPTER XXI

ON THE STREET

As Mr. Cook left the room the two boys heard the automobile come up the driveway and stop in front of the house. Mrs. Cook and Louise were to spend the evening with an aunt of Bob's a short distance down the street, and Mr. Cook was to take them there in the car. Bob and Hugh waited until they should all leave for they did not want to be seen by any one in their disguises.

Presently they heard the car start off and they knew the coast was clear. Silently they slipped down stairs and out the front door. By the side of the house they paused for a consultation.

"These whiskers itch awfully," exclaimed Bob.

"So does this mustache," said Hugh. "I guess we'll have to endure it though."

"Where shall we wait?"

"Won't Lena come out the back door?"

"I guess so. At any rate she'll have to come around and go down the front walk, there's no other way for her to get out of the yard."

"Let's cross the street and wait there then."

They followed that plan and presently were standing side by side in the shadow of a tree on the opposite side of the street. Lena could be expected to appear at any minute and they kept a sharp lookout for her.

"What do you suppose is ahead of us to-night?" asked Hugh in a low tone.

"I wish I knew."

"I hope we aren't going off on a wild goose chase."

"You've been saying right along that we ought to watch Lena," Bob reminded his friend.

"I know that and I think it's a good plan. All I say is that she may fool us in some way if we're not careful."

"How do you suppose Mr. Wernberg's getting along in the hospital?"

"I don't know," said Hugh. "I must say though that I'm more interested in Lena."

"I'd like to see our old friend, the false detective."

"So would I. What do you suppose he is—"

"Ssh," hissed Bob suddenly.

Around the corner of the Cooks' house came a woman. She walked briskly and a moment later had reached the street. She gazed apprehensively up and down while the two boys shrank farther back into the shadow; then she started off in the direction of the city's business district.

"That's Lena," whispered Bob. "Come on."

On the opposite side of the street and perhaps a hundred paces in back of the hurrying woman the two boys followed.

"We'll have to keep closer than this when she gets down town," whispered Hugh.

"I know it," agreed Bob. "She'd get suspicious now though."

Now and again Lena stopped and glanced behind her. Every time she did so the boys stopped too; evidently she was afraid of being followed. They met few people and those who did pass them apparently took them for a couple of tramps, for they paid no particular attention to them.

A little distance down the street Lena turned the corner to her right. The two boys as a consequence had to run in order not to lose sight of her. They were fearful lest she should slip away from them and therefore were greatly relieved when they came to the turn and saw her still in front of them.

A few moments later she turned again, and then presently, turned still a third time.

"She's trying to lose us," whispered Bob.

"Maybe not," said Hugh. "This is Elm Street."

"Where's twelve eighty-two!"

"On the next block."

The white stucco house was on the same side of the street with the boys, and as Lena came opposite it she crossed over. Bob and Hugh stopped short under a large maple tree whose trunk cast a shadow affording ample protection from a nearby arclight. From this vantage point they watched the woman they were trailing.

"She's going in," whispered Bob, clutching Hugh's arm excitedly.

Lena turned in from the side walk and started toward the steps of the white stucco house, number twelve eighty-two. Half-way up she paused irresolutely. She acted as if she was puzzled as to what she should do; finally she turned, descended the steps rapidly and continued on down the street.

"That was queer," whispered Bob.

"It looked as though she lost her nerve."

"Why should she be scared to go in where her gang is!"

"Don't ask me. Come on."

Once again they took up the chase. Lena seemed to walk more swiftly than ever now, and it was not an easy task to keep pace with her and still not be seen. The night was dark with low-hanging clouds, the street lamps affording the only light available. Ahead they could see the reflection from the lights of the main street of the city.

"Do you suppose she dropped a note or anything on that porch back there?" demanded Hugh suddenly.

"I didn't see her do anything like that," said Bob.

"Nor I. At any rate I guess the best thing we can do is to stick close to her."

"Yes, and we'd better keep closer too, now that we are coming to where the stores are. We'll lose track of her if we don't."

"Do you suppose any one will notice that we're disguised?"

"I hope not. There's usually a big crowd on the streets Saturday night though."

"We'll hope for luck," said Hugh earnestly.

They quickened their paces until they were scarcely more than seventy-five feet in back of Lena. There were many people passing them in both directions now, and apparently Lena was not as suspicious as she had been; she glanced behind her no more.

Presently they turned into the main street. The sidewalks were thronged with people and everything was lighted up brilliantly in the glare of arclights and shop windows. Lena was just ahead of the boys and it was not an easy task to follow her in the crowd.

Music sounded down the street. A troop of cavalry was approaching and every one lined the curb to see them pass. Lena stopped and the boys took their places directly behind her. Every trooper was mounted on a coal black horse, and they made a fine showing as they drew near; the crowd began to cheer and many waved small American flags that they were carrying. Women waved their handkerchiefs as the horsemen passed, and much to both Bob's and Hugh's surprise Lena waved her handkerchief and clapped her hands with the others.

"What do you think of that?" whispered Bob.

"Bluff," said Hugh. "She's clever."

The crowd began to break up and presently was moving up and down the street again. Lena started on her way once more, and almost at her heels followed Bob and Hugh. They were beginning to wonder whether they were following a false clue. It might be that Lena had dropped a message on the porch of the house on Elm Street, and if so her work was probably done and there could be no object in following her farther.

Suddenly Hugh seized Bob by the arm. "Look at this man coming," he hissed.

Not thirty feet distant and walking directly toward them was the false detective. There could be no mistaking him. Bob and Hugh, forgetting for the moment that they were disguised were fearful lest he should recognize them as well. A moment later, however, an interesting event happened right before their eyes, and they forgot all else.

As the "detective," the man with whom they had fought that morning, the man who had blown up the deserted house, and whom they suspected of having tried to blow up the railroad bridge in the afternoon, passed Lena he held a slip of paper in his left hand. As she went by she took it with her left hand, though as far as the boys could see the two conspirators had not even looked at each other.

Lena continued on down the street as if nothing had happened, while the detective also kept on as though unconscious of having seen Lena at all. He passed the two boys without even a glance.

Bob and Hugh stopped short.

"What do you think of that?" demanded Hugh. "What'll we do?"

"Follow them," said Bob quickly. "You follow him and I'll trail Lena."

Without another word the two boys separated.



CHAPTER XXII

BOB ACTS QUICKLY

Bob had almost lost sight of Lena through this temporary delay and he hurried ahead through the crowd, bumping into several people, and drawing black looks from many for his rudeness. He was in a hurry, however. He had to catch up with Lena, and there was no time to be polite.

Lena too was hurrying. She threaded her way in and out among the throngs of people, and Bob was hard put to it to keep pace with her. As he rushed along he became more and more puzzled and confused as to what was taking place. There was no doubt in his mind that Lena and Heinrich were working in the interests of Mr. Wernberg and therefore were to be watched closely. Apparently Lena was in league with the fake detective too, else why should he stealthily slip a communication into her hand?

But the detective had blown up the house when Mr. Wernberg was within it and had nearly caused his death. If they were all working together how was that fact to be reconciled with what had befallen him? Probably Mr. Wernberg had been injured accidentally as Sergeant Riley had explained. At all events Lena was hurrying along through the crowd and Bob's task was to follow her. His father was watching Heinrich and it would never do for Bob to let his quarry escape him.

Lena followed the main street for several squares. The crowd was still thick, but Bob kept his eyes on her. Presently she turned down a side street, where it was easier to follow her and Bob heaved a sigh of relief. He was sure he could keep track of her now, and his mind was easier. They passed fewer people all the time, and now the only illuminations were the street lamps and an occasional arclight.

Bob dropped further behind. His one wish was to avert suspicion on Lena's part, and the sight of a tough-looking man with heavy black whiskers, old clothes, and a dilapidated slouch hat dogging her footsteps might well have made her uneasy.

Every hundred feet or so Lena cast a quick glance over her shoulder. Bob did not walk on the stone pavement, but skulked along in the shadow of the hedges and fences except when a passerby came along. Consequently whenever Lena looked behind her he stood still. It was exciting work.

A half-mile or so down the street Lena stopped. She stood under one of the street lamps, and after a sharp glance in all directions, stealthily drew a piece of paper out of the bag she carried. She was plainly nervous, and Bob watched her intently. She was about to read the note that the fake detective had handed to her.

It took Bob only a second to make up his mind. The occasion called for quick action and he acted quickly. Running swiftly and silently on the moist earth, he stole up behind Lena. She was standing still, deeply engrossed in what she read on the paper she held in her hand. Consequently she was unaware of Bob bearing down upon her.

When he was about ten feet behind her, Bob suddenly dashed forward, even more swiftly than before, and before the startled cook knew what was happening he had snatched the paper from her hand and was speeding away with it. He ran only for a few steps, however. An exposed root from one of the big maple trees that lined the sidewalk caught his foot; he tripped, was thrown violently forward, and fell sprawling on his face. He did not relax his hold on the paper, however. It was crumpled, but he held it tightly clenched in his hand.

The fall jarred him considerably. The knee of his trousers was torn and his hand scraped. His hat fell off, and as he slid along the ground on his face, half of his false whiskers were ripped off. He picked himself up as quickly as he could, however, and turned around to see what Lena was doing.

She was nowhere to be seen.



CHAPTER XXIII

UNDER THE LIGHT

Hugh turned quickly and followed the fake detective through the crowd. The man sauntered along as if he was in no hurry whatsoever, so that Hugh too had to walk very slowly. The man stopped and looked in at the windows of many of the stores, and close behind him every time stood Hugh; he was at a loss to account for this behavior on the part of the man he was following, as his dilatory tactics were in sharp contrast to the way in which Lena had hurried.

Every few moments the fake detective took out his watch and looked at the time. Hugh decided he must have an engagement for later on in the evening, and that until then there was nothing for him to do.

As nine o'clock struck on the City Hall clock the man whom Hugh had been following stepped into a drug store. There was a row of telephone booths along one side of the store and the man entered one of these and shut the door. Hugh could see him through the glass, as he took down the receiver and gave the number to central.

Hugh loitered around the store, looking at the various articles offered for sale under the numerous glass cases, while at the same time he kept a careful watch on the telephone booth. The man talked for what seemed a long time and finally Hugh was afraid to remain in the store any longer lest he should arouse suspicion. He went out and took his stand near the front entrance, in a spot where he could see every one who came in or went out.

There were large posters in the store window urging men to enlist in the army and the navy. Pictures of trim looking soldiers and sailors were on the posters and the cards bore urgent calls for recruits. "Your country needs you now," ran the legend and Hugh sighed to think that he was not yet old enough to answer the call. His ancestors had been Americans for many generations, they had fought and bled in every war the country had declared, and Hugh wanted to live up to the traditions they had established. He realized too that his country did need men, perhaps as never before. He knew that in order to defeat Germany every ounce of strength the country possessed would have to be thrown into the struggle. As his father said, "Germany is beaten, but they don't know it yet, and it may take years of stubborn fighting to teach them."

Hugh's thoughts were interrupted presently by the reappearance of the fake detective; he came out of the drug store and turning to the right walked off down the street. He hurried now, so that Hugh had trouble in keeping pace with him. The man walked swiftly as if he had some definite objective in view, and Hugh realized that probably the crisis of the whole affair was not far distant.

Suddenly Hugh spied a rough-looking individual approaching them from the opposite direction; his clothes were dirty and the knee of one of his trousers legs torn. He recognized Bob at once.

The fake detective eyed Bob as he passed, but probably took him for some tramp passing through town; certainly he looked the part. Every one in the crowd edged away from him as he drew near, and Hugh could not help wondering if he looked as tough as his friend.

Bob recognized Hugh as he came along without a word of greeting, turned about and walked along beside him. He had seen the fake detective on ahead and though there was no chance for explanations, he knew that Hugh was still on the trail.

In a few moments they came to the City Hall. The detective looked up at the clock on the tower, compared the time with his watch and then took his stand under one of the electric lights on the street in front.

"He has a date here," whispered Hugh. "We'll have to cross the street."

They crossed over and under the pretense of looking at the billboards in front of the moving picture theater kept watch on their man.

"Where've you been?" demanded Bob.

"Just following that man around," said Hugh. "What happened to you?" and he looked at his friend's torn and dirty clothes.

Bob related the story of his experiences. He had searched vainly for any trace of Lena and failing to find her had resolved to take one turn along the main street and then go down to the factory. He had met Hugh as has been told.

"But the paper Lena had," exclaimed Hugh. "You got it you say?"

"I certainly did."

"What did it say?"

"Read it," said Bob, handing the crumpled sheet over to his companion.

Hugh started to unfold it, but before he could do so, Bob grasped him by the arm and pointed across the street. "Look," he exclaimed.

A woman had joined the fake detective under the light, and the two were talking together.

"It's Lena!" said Hugh excitedly.

"But where did she come from?"

"I don't know, but there she is all right."

"He's mad about something," said Bob. "Probably because she lost that piece of paper."

"That'll prove to him they're being watched."

"I wonder if they suspect us."

"Let's hope not, yet," said Hugh earnestly. "There they go," he added a moment later, as Lena and the fake detective started down the street. They still were talking excitedly together and it was hard to tell from their manner whether the man was threatening Lena or pleading with her.

"Another chase, I suppose," sighed Bob. "I'm getting tired."

"Not a chase on foot anyway," said Hugh, for just then the fake detective hailed a passing cab; he and Lena stepped into it and a moment later were being driven rapidly away.



CHAPTER XXIV

AT THE FACTORY

"Well," exclaimed Bob in dismay, "I guess they got rid of us that time."

"Why have they?" demanded Hugh. "Why can't we hire a cab and follow them?"

"Have you got any money?"

"Not a cent."

"Neither have I. I guess we're left."

"Aren't we fools?" cried Hugh angrily. "How could any one be so stupid?"

"There's no use in crying over spilt milk," said Bob. "The thing for us to do is to decide what we ought to do next."

"Let's go down to the factory; I don't see what else we can do."

"All right," said Bob disconsolately. "I do hate to have to go and tell father that we've been tricked and beaten though."

"He can at least get the police to come down and help guard his factory," said Hugh. "Probably no harm will come to it if they do that."

"But how do you know his factory is to be attacked? It may be they are planning other damage to-night. We might have had a chance to stop it if we'd followed those two, and now they've got away from us."

"Your father ought to have reported Lena and Heinrich to the police anyway."

"He said he'd keep watch of Heinie, and no doubt he has. He expected we'd do as well for Lena. We'd better go down and see him about it."

"Let me read this paper first," said Hugh. He once again started to unfold the crumpled sheet that Bob had stolen from Lena.

"You can't read it."

"Why not?"

"Try and see."

Hugh unfolded the paper and gave it one look. "Why it's written in German," he exclaimed in surprise.

"I know it is; that's why I said you couldn't read it."

"We must get it translated."

"Let's take it down to the factory. We can get Karl Hoffmann to tell us what it says."

Without further ado they set out. They walked swiftly and exchanged but few words, for they were both occupied with their own thoughts; a feeling that something was hanging over their heads oppressed the two boys. The country was at war and plotters and spies were abroad in the land. The events of the last two days had convinced them that High Ridge had its share of mischief makers, and they felt sure that that very night a blow would be struck.

A walk of twenty minutes brought them to the factory. The low, brick buildings loomed ghostly in the darkness, with only here and there an electric light burning inside as protection against thieves. The small brick office was situated in front of the other buildings and here a light was shining brightly.

A guard challenged them. Bob recognized the man as one of his father's employees, and soon convinced him that he and Hugh were all right. They passed on and a moment later were in Mr. Cook's office. Mr. Cook was seated at his desk and in a chair opposite him Sergeant Riley was ensconced.

"Well," exclaimed the sergeant as the boys entered, "if ever I saw two hard looking bums you two are it. 'Tis a wonder one of my men didn't run yez in."

"We were sort of afraid of that," laughed Bob. "No one bothered us though."

"Where's Heinrich?" inquired Hugh.

"In the next room," said Mr. Cook. "Where's Lena?"

"We lost her."

"What do you mean?"

Bob told his father what they had done.

"It looks serious," said Mr. Cook thoughtfully. "Sergeant Riley has just come from the hospital and he brought me news of Mr. Wernberg."

"How is he?"

"He's better; he talked a little this evening."

"Did he?" cried Bob eagerly. "What did he say?"

"He didn't talk connectedly," said Mr. Cook. "He was only conscious for a few minutes, and wasn't well enough to hold a real conversation."

"But he must have said something."

"He did. He mumbled about bombs, and plans. He talked a lot about a factory, and kept saying, 'hurry,' over and over again."

"Didn't any one ask him what he meant?"

"I asked him myself," exclaimed Sergeant Riley, "but he was not well enough to answer me or understand what I was saying."

"Do you think he referred to this factory?" inquired Hugh.

"The sergeant thinks so," said Mr. Cook. "There are only two others in High Ridge that they would try to destroy probably, so you see the chance is one in three that he was speaking of this one."

"I can't imagine a man plotting such things," said Bob bitterly. "He thinks he's helping Germany I suppose."

"Huh," snorted Bob. "A nice kind of man that will earn his living in a country and then try to blow it up. Is he going to get well?"

"The doctors say he has an even chance," said Sergeant Riley.

"Well, all I hope is," said Bob, "that when he does get well they take him and put him in jail for about fifteen years. Have you got plenty of guards, father?"

"I think so," said Mr. Cook. "I've got all I can get anyway."

"Hugh and I are ready to help you know."

"I know it, and I may use you later to-night; we will need them more then probably. In the meantime why don't you go and lie down for a little while?"

"We've got a paper here to be translated first," said Bob.

"Give it to me," exclaimed Mr. Cook. "I'll call Heinrich in."

In response to his summons Heinrich soon appeared from the next room. He looked pale and haggard as though he was tired and worn and worried. He glanced from one to another of the people gathered around the desk, but even his old pals, Bob and Hugh, gave him no more than a fleeting smile.

"We have a letter or something here written in German, Heinrich," said Mr. Cook. "I'd like to have you translate it for us, please."

Heinrich took the paper that was held out to him. Every one watched him narrowly as he looked at it, and were amazed to see him suddenly turn deadly white. His hand shook violently and he had to lean against the desk to keep from falling. He gazed at Mr. Cook pleadingly, a hunted look in his eyes.

"What does it say?" asked his employer.

Heinrich gasped and almost choked once or twice. He swallowed hard and finally found his voice again. "I don't know," he replied.

"You mean you can't read the German?"

That seemed to be as good an excuse as any, so Heinrich seized upon it eagerly. "Yes," he stammered. "That iss it."

"I don't believe you," said Mr. Cook calmly.

"Please, Mr. Cook," begged Heinrich. "Don't ask me to read it."

"But I want to know what it says."

"I can't read it."

"You don't mean that," said Mr. Cook. "You certainly can read it."

"I can't read it," Heinrich repeated. It was plain to be seen that he was suffering great mental agony; he glanced about him fearfully as if he expected to be attacked suddenly. He looked at the paper again and an involuntary groan escaped him. He appealed to Mr. Cook.

"Please let me go home," he pleaded.

"You won't even leave this room until you've read what that says," exclaimed Mr. Cook, becoming angry and irritated at Heinrich's refusal to do as he said. Bob had seen their chauffeur stubborn before, however, and he knew that if he made up his mind to a thing he was as obstinate as only a German can be.

Heinrich merely looked at Mr. Cook sorrowfully.

"I'm a policeman you know," said Sergeant Riley sharply.

Heinrich ignored the implied threat completely.

"Come on, Heinie," urged Bob cajolingly. "Don't be foolish."

"I can't read it," said Heinrich again.

"You know," said Mr. Cook, "we're suspicious of some things you have done already, Heinrich. Don't make it worse if you can help it."

"I can't read it," said Heinrich.

Bob knew the chauffeur well enough to know that there was no use in arguing with him further; it would only be a waste of breath and time.

"I don't want to turn you over to the police, Heinrich," said Mr. Cook. "That is what I shall do, however, unless you do as I ask."

Heinrich turned paler than ever at this, but the words had no other effect on him. "I can't help it," he muttered doggedly. "I can't read it."

"Let me see the paper," said Sergeant Riley. Heinrich handed it over.

"What's the little alligator doing on it?" queried the sergeant curiously.

"Heinrich can tell you," said Mr. Cook. "What does it mean, Heinrich?"

The chauffeur made no reply. He looked at the floor dejectedly but offered no remark. Now and again he glanced about him nervously.

Just at that moment the door of the office was opened and Karl Hoffmann entered. Heinrich looked at the newcomer, and there was hatred in his very glance. His fists were clenched tightly so that his knuckles showed white. He opened his mouth as if about to speak, and apparently with difficulty checked himself.

Karl Hoffmann took in the scene with one glance and was plainly surprised by the gathering. At first he did not recognize Bob and Hugh, who still wore their disguises. Both boys greeted him, however, and laughed at his surprise when he discovered who they were.

Karl himself looked pale as though he was working under a high tension; certainly the times were strenuous. He held something in his hand that apparently he wished to give to Mr. Cook. Before he could speak, however, Mr. Cook anticipated him.

"Here is a paper, Karl," he said. "It has German written on it and I'd like to have you translate it for us if you will."

As Karl took the paper Heinrich started forward as if he would protest. He was pale and his lips were shut tight; his face was the picture of desperation. He looked as if he had reached the limit of his endurance and must speak. For a moment Bob thought he was going to spring at Karl. Heinrich finally got control of himself, however, and relapsed into a sullen calm.

Karl took the paper and looked at it carelessly. Suddenly his jaw dropped and he started back aghast. He turned almost as pale as Heinrich had done.

"Where did you get this?" he demanded.

"Tell us what it says," urged Mr. Cook.

"This is certainly remarkable," said Karl, though by this time he had partly regained control of himself.

"He won't read it, I bet," said Heinrich fiercely.

"Keep quiet, Heinrich!" exclaimed Mr. Cook sharply. "Karl is a good American; of course he'll read. Won't you, Karl?"

"Certainly I will," said Karl easily. He had entirely recovered his composure now.

He had just opened his mouth to speak when he was interrupted by a volley of shots outside. Instantly everything was in confusion. Every one made a rush for the door and as it was yanked open a piercing shriek rent the air.



CHAPTER XXV

A STRUGGLE IN THE DARK

The woman's scream was so full of terror, so agonized, and so blood-curdling that for a moment the mad rush out of the door was halted. Every one stopped short in horror and amazement.

Sergeant Riley was the first to regain his senses. "Come on!" he shouted and plunged out into the night. Close at his heels followed the others. That is, all except Heinrich; he dashed into the room adjoining the office and remained there unnoticed.

The air was filled with shouts and cries. Men ran hither and thither, black shapes flitting up and down like shadows.

"Spread out!" shouted Sergeant Riley. "Circle the factory and don't let any one escape."

Bob and Hugh unconsciously kept close together in spite of the sergeant's orders. One end of the factory was situated on the shore of the Molton River, and toward the river bank the two boys made their way.

"What a scream that was," shuddered Hugh.

"Awful," cried Bob, and then he tripped over something lying on the ground, and pitched forward headlong on his face. A moment later he had regained his feet.

"What tripped you?" demanded Hugh.

"Look!" said Bob, shivering as he spoke. He pointed to a misshapen heap of something lying on the ground at his feet. "It was soft, like a body."

"The woman who screamed," cried Hugh in terror.

"Strike a match."

"I haven't got one."

"We must pick her up and carry her into the office."

"But she may be dead."

"Suppose she is," exclaimed Bob. "We've got to do it just the same."

"This is terrible," cried Hugh. "Can't we get some one to do it for us?"

"Every one is busy."

"Where's Karl?"

"He's busy, too. Come on, Hugh, we must do it. If she's not dead now she may die while we stand here and talk about it."

Hugh braced himself for the task. They could distinguish the vague outlines of the woman's form, as Bob stationed himself at her head and Hugh grasped her feet.

"All ready," said Bob. "Lift her up."

"Suppose we are attacked while we're carrying her."

"Lift her up, will you?" demanded Bob angrily. "What's the matter with you, Hugh?"

Bob took hold of her shoulders and Hugh grasped her ankles. She was heavy and absolutely limp so that it was very difficult to lift her from the ground. The two boys exerted all their strength, however, and presently were able to start on their way back to Mr. Cook's office, panting and straining as they went. The distance was not great, fortunately, and soon they opened the door of the office and deposited their burden on the floor.

"Why," gasped Bob, starting back in surprise. "It's Lena."

"What?" demanded Hugh.

"It certainly is. Look at the blood on her shoulder."

"Is she dead?"

"I don't know." He took hold of Lena's wrist and felt for her pulse. "Her heart is still beating," he announced a moment later.

"Hadn't we better get a doctor?"

"I should say so," exclaimed Bob. "Call up Doctor Clarke and tell him to come down here just as fast as he can."

Hugh hastened to obey, while Bob secured a towel soaked in water and began to bathe the wounded woman's face. How had it all happened? Perhaps one of the factory guards had surprised her at some criminal work and had shot her as she fled. Bob did not know enough to understand whether she was badly wounded or not; at any rate she was still bleeding profusely.

Presently Hugh reported that the doctor would be down just as quickly as he could. He had promised to start at once.

"What shall we do?" inquired Hugh.

"Don't you think we ought to stay here with Lena?"

"I don't see that we can do anything for her, and we may be needed outside. Where's Heinie? Why don't we leave her with him?"

"Where is Heinie anyway?" exclaimed Bob. He hurried to the door of the adjoining room, but there was no trace of the missing chauffeur.

"He's gone, I guess," said Hugh. "When every one rushed out in the excitement he must have slipped away. We'll never see him again."

"How stupid of us," cried Bob. "Every one clean forgot him, I guess."

"His escape doesn't settle what we have to do," said Hugh.

"Let's go out and leave her here, I say. We don't know anything to do for her. Anyway you told the doctor where to come, didn't you?"

"I did."

"Come on then," and Bob hurried out, with Hugh following close behind.

In front of the office they stopped for a moment, peering intently all about them and straining their ears for every sound. Bob remembered the big hickory stick of his father's and stepped inside again to get it.

"We're taking chances prowling around here unarmed," said Hugh when his friend had joined him once more.

"I know it, but what can we do?"

"Nothing, I guess. Where do you suppose the others are?"

"Let's go find them."

Again they started in the direction of the river, not in a mad rush this time, but slowly and carefully picking their way. They skulked along in the shadow of the factory walls, ready for any emergency that might arise. They kept close together and if the truth were known both boys would have been very glad to have had an armed companion with them.

They had covered perhaps a hundred and fifty feet or so, and ahead of them could just make out the dark bank of the river. Suddenly they saw a man appear around the corner of the building, running toward them. Bob and Hugh crouched against the brick wall and waited for him to come near. All at once Bob recognized the stranger and started forward.

"Karl," he cried.

The man halted.

"Where are you going?" asked Bob. "Where are father and the others?"

"Down by the river," replied Karl and once more broke into a run. A moment later he was lost to sight in the darkness.

"Seems to me he's in an awful hurry," remarked Hugh.

"Father had probably sent him on an errand," said Bob. "Let's hurry and see if we can't find father and Sergeant Riley."

"Who do you think shot Lena?" asked Hugh.

"I don't know. We'd better not talk here now."

"Do you suppose it could have been the fake detective?" said Hugh regardless of Bob's advice.

"I don't know, but I don't see why he should shoot one of his own gang."

"He blew up Mr. Wernberg though."

"I know it, but I can't understand it, and as I said I don't think we ought to talk here."

They proceeded in silence. Both boys were eager to join the others and they wondered what they could be doing down by the river. Perhaps they had captured the plotter and had dispatched Karl for rope or handcuffs to secure him. At any rate nothing suspicious had happened since the shots had first been heard.

The boys had progressed but a short distance further, when suddenly a great tongue of flame shot heavenward between them and the river. An ear-splitting detonation followed, and the very earth was rocked by an enormous explosion. Both boys were thrown violently to the ground by the force of it, while showers of earth, bricks, and material of all kinds pelted down all about them.

A moment later the boys were on their feet, still partly stunned and undecided as to whether they should run or not.

"There may be another one coming," warned Hugh.

While they hesitated a man suddenly appeared running swiftly away from the direction of the explosion.

"Hey there!" challenged Bob. "Who are you?"

For answer there came the flash of a revolver and a pane of glass in the window close beside the boys' heads was shattered.

"Stop!" shouted Bob at the top of his voice and regardless of danger he started in pursuit of the fleeing man. Hugh was not to be left behind at such a time and together they raced after the fugitive.

Suddenly he stopped, raised his right arm, and hurled his revolver. It struck the ground directly in front of Hugh, spun around a number of times and hit him a sharp blow on his shin bone as it caromed.

"Let it alone," cried Bob.

"It must be empty."

Both boys were fleet of foot, but in the first fifty yards of the race the man gained on them. It was plain to see that unless something happened they would soon be outdistanced. Bob realized that the time had come when chances were to be taken. He raised his father's hickory cane above his head, whirled it around a couple of times, and sent it spinning in the direction of the fleeing figure ahead.

The one chance in a hundred was successful. Bob's aim was true and the heavy stick flew straight to its mark. As the man ran, one end of it protruded itself between his legs; he was tripped up and, losing his balance, fell sprawling to the ground. Almost instantly he was on his feet again, but the delay occasioned by his fall had been almost sufficient to enable the boys to catch up with him. They were barely two steps behind him now.

"Tackle him!" shouted Bob.

Like two ends going down the field to get the quarterback who is receiving the punt Bob and Hugh leaped forward at the same time. They had both had experience in football and it stood them in good stead now. The man went down, both boys literally swarming all over him.

"I've got his legs, Hugh," cried Bob. "Grab his arms."

The man kicked and struggled with all the strength that was in him. Bob hung on for dear life, however. He held one of the man's feet in each hand and threw his body across his legs to hold them down. Hugh scrambled forward and hurled his entire weight across the man's chest. Their prisoner's fists were going like flails, but Hugh persisted. The thought of this German plotting against the United States was more than he could endure and he dealt the man a stunning blow squarely in the face.

A moment later the man's arms and legs were tightly pinned to the ground while the two boys sat astride him, complete masters of the situation.

"I'd like to pound his head off," cried Bob fiercely. "Just look at that fire."

The bomb had done its work, and already the flames were mounting higher and higher over the damaged portion of the factory. The fire whistles were blowing violently; some one had turned in the alarm promptly anyway.

"What shall we do with him?" panted Hugh.

"You didn't knock him out when you hit him, did you?"

"No. He's all right."

"Let's get him on his feet and take him up to the office then."

"Hang on tight."

"Don't worry about that. If he tries to get away we'll choke his head off."

Whether or not the man understood these remarks he offered no comment. Hugh held him by one arm and Bob by the other. They yanked him to his feet and marched him off in the direction of the factory office. Strange to say their prisoner offered but little resistance; he dragged his feet somewhat but followed along sullenly.

Presently there was a clatter and a clang of bells and the fire engine dashed into the yard, shooting sparks in a broad yellow stream from its stack. There was much shouting and giving of orders, and a moment later the hose cart, and the hook and ladder made their appearance.

Whether or not it was the distraction caused by these events, Bob and Hugh never could explain to themselves. At any rate they must have relaxed their caution and paid less attention to their prisoner than they should, for with a sudden violent twist of his body he wrenched himself free and was gone.



CHAPTER XXVI

AN EXPEDITION IS PLANNED

"Catch him! Catch him!" shrieked Bob hysterically.

The man darted away in the direction of the fire engine with the two boys pursuing him at top speed. The fugitive was fleet of foot, however, as had already been proved to Bob and Hugh. He was gaining rapidly on his pursuers, while their shouts and calls were lost in the general hubbub and confusion incident to the fire.

A short distance along the course of the chase two barrels supporting a plank were standing. As the man passed them he hesitated long enough to dislodge the plank and upset the barrels. They rolled directly in the path of the two boys, one of them causing Hugh to trip and fall. Bob kept up the chase, however, but the factory yard was now filled with people attracted by the fire and the man he followed soon eluded him in the crowd.

There was nothing for Bob to do, but give up. He turned back and presently discovered Hugh limping toward him.

"Hurt yourself?" he demanded.

"I skinned my knee. Where's our man?"

"He got away in the crowd."

"We're a couple of fine ones," exclaimed Hugh disgustedly.

"We certainly are," echoed Bob. "I'm getting so I'm ashamed to see father; all I do is report failures to him."

"We'd better go back to the office and see him though."

They returned to the office and at the door met Mr. Cook coming out. He greeted the boys heartily, for he had been worried about them.

"I'm glad to see you two," he exclaimed. "I was afraid something had happened to you."

"Oh, we're all right," said Bob. "Where's Lena?"

"What do you mean?" demanded his father. "I haven't seen her."

"Well, just look at that," said Bob, pointing to a dark stain on the floor. "That's where she was lying; she was the woman who screamed."

"You don't tell me!" exclaimed Mr. Cook. "Was she badly hurt, and who shot her?"

"We can't answer either question. All we know is that we found her outside, unconscious, and brought her in here. She was wounded in the shoulder and bleeding badly. We left her here and went out again."

"Why didn't you telephone for a doctor?"

"We did. We sent for Doctor Clarke."

"And here's a note from him on the table here," exclaimed Hugh. As he spoke he handed the piece of paper to Mr. Cook.

"'Have taken patient to hospital in order to remove bullet,'" Mr. Cook read aloud.

"Golly," exclaimed Hugh. "There's lots going on around here, isn't there?"

"Too much," said Mr. Cook soberly. "I hope that explosion hurt no one."

"How about the fire?" asked Bob.

Sergeant Riley arrived just then and reported that the fire department had the blaze under control and that it was only a question of a short time before it would be entirely out.

"'Tis lucky it is no worse," he said seriously.

"And it's also lucky that my insurance will pay for it all," added Mr. Cook.

"The thing that makes me mad is that the German divils who exploded the bomb all got away," exclaimed the sergeant bitterly.

"Were there more than one of them?" asked Bob.

"We don't know for sure," replied Riley. "One o' the men told me he saw two of them running away, but he may have been mistaken."

"Well, Hugh and I caught one of them," said Bob.

"You did!" almost shrieked Sergeant Riley, bouncing out of his chair. "Where is he then?"

"We don't know."

"What do yez mean?"

"He got away from us, and we lost him in the crowd."

"Oh, my boy, my boy," wailed Riley, nearly in tears. "Why did yez ever let such a thing happen to you? That was our chance to put a crimp in the whole gang, and now I suppose they'll be after blowing things up worse than ever."

"But we didn't do it on purpose," protested Bob meekly.

"I know yez didn't," said the sergeant. "If I had only been there! I can tell yez that if ever I get my hands on one of them fellers he'll never get away."

"It's too bad," exclaimed Mr. Cook. "Still I don't think the damage they did here will seriously interfere with our work for the Government."

"I hope not," said Sergeant Riley fervently. "I hope yez can make enough ammunition to blow the bloody Germans clean out of France and Belgium and sink every blooming submarine they have on the ocean."

"I hope so, too, Riley," said Mr. Cook. "There's no room in a decent world for people who act as the Germans do."

"First of all though we've got to fix it so they can't interfere with our factories over here," exclaimed the sergeant. "I wish we could catch this gang."

"What happened to Heinrich?" asked Bob. "Did he get away?"

"He did not," said Sergeant Riley. "One of my men escorted him to the police station where he'll be waiting until we want him."

"He didn't say what was on that sheet of paper, did he?"

"Not yet."

"Where's Karl?" asked Bob. "He was going to read it for us."

"I don't know where Karl is," said Mr. Cook. "He hurried off to look after part of the factory just before the explosion occurred. He's a good soul, Karl. I wish all the German-Americans were as loyal as he is."

"Did one of the guards shoot Lena?" Hugh inquired.

"No," replied Mr. Cook. "Karl and I asked them all, and not one of them had even seen her. It's a peculiar thing."

"I wonder if our friend the fake detective could have done it."

"He wasn't the feller you caught, was he?" asked Riley.

"No," said Bob. "Our man had whiskers, didn't he, Hugh?"

"Yes," said Hugh.

"They may have been false," suggested the sergeant. "You've got false ones on."

"And they still itch terribly."

"Why don't you take them off?" inquired Mr. Cook. "I guess you won't need them any more to-night, will you?"

"That depends on what is going to happen," said Bob. "Have you any plans, Sergeant?"

"I wish I had," exclaimed Riley. "What I want to find out is where this gang has its headquarters. When I know that I'll go there and pay a call."

"I know where it is," said Bob.

"You do?" demanded the sergeant in surprise. "What are you two anyway; a couple of young Sherlock Holmes?"

"Not at all," laughed Bob. "We are suspicious of a certain house though, and it might be worth while to go up there and take a look around."

"That's the stuff," exclaimed Riley eagerly. "I'll swear you all in as deputy sheriffs, and we'll get guns for yez and go up just as soon as we can."

"We're only suspicious of this house, you know," said Bob.

"Where is it?"

"Twelve eighty-two Elm Street."

"I heard Heinrich say something about Elm Street," exclaimed Riley. "Your clue may be a good one after all."

"Poor old Heinie," murmured Bob.

"Poor old nothing," cried Riley. "Who feels sorry for a German plotter?"

"But Heinie was stupid and they probably made a fool of him."

"The fact remains, however, Bob," said Mr. Cook, "that Heinrich evidently was in with this gang and therefore he ought to be punished."

"You're dead right, Mr. Cook," exclaimed the sergeant. "No matter whether a man's been made a fool of or not, if he's dangerous he ought to be locked up."

"I suppose so," Bob agreed. "I feel sorry for him though, more sorry than I do for Lena. She has more brains than Heinie and ought to know better."

"Meanwhile we ought to be on our way to Elm Street," exclaimed Sergeant Riley. "Come on, boys, let's get started."



CHAPTER XXVII

A RAID AND A SURPRISE

Mr. Cook's automobile was still standing outside, and a few moments later the little party of four were seated in it and on their way to the police station. Bob was at the wheel.

Upon their arrival it was the work of only a few moments to have Mr. Cook and the two boys sworn in as deputy sheriffs. Bob and Hugh retired to the wash room and after more or less trouble succeeded in removing the false crop of hair from their faces.

Sergeant Riley ordered two policemen in uniform to go with them, and when Mr. Cook, Bob and Hugh had been equipped with pistols and heavy night sticks, the band, now increased to six, were ready to proceed. They used the Cooks' car again and presently were gliding silently along in the direction of Elm Street.

Two blocks distant from number twelve eighty-two Bob stopped the car and every one got out. A short consultation was held and it was decided to separate. Consequently Mr. Cook, Hugh, and one of the policemen went down a side street in order to go around the block and approach the house from the opposite direction. Bob, Sergeant Riley, and the other policeman were to wait a few moments and then move on up Elm Street. It was thought best to have Bob with one party and Hugh with the other as both boys knew the house and could lead the way with no possibility of mistake.

It was exciting work and Bob and Hugh both felt very important and elated at being allowed to accompany the officers on this raid. Furthermore they were going to see the inside of the mysterious stucco house, and perhaps clear up the whole mystery of the German plot and spy system in High Ridge.

After a few moments' wait Bob, Sergeant Riley, and the policeman started to move slowly up the street. They met no one on the way, for it was now after midnight and people were mostly in bed. Only one house had a light burning as far as they could see; that house was a white stucco one, number twelve eighty-two and the light was on the third floor.

"Here come the others," whispered Bob to Sergeant Riley as they drew near their destination.

Orders had already been given and every one knew what he was to do. One of the policemen went around to the rear of the house and took his position by the back door. Mr. Cook was to guard the front entrance, and both men had instructions to do everything necessary to prevent the escape of any of the inmates of the house.

The remaining four members of the party, led by Sergeant Riley, stole noiselessly up the steps and approached the front door. Riley took a bunch of keys from his pocket, inspected the lock, and then selected one of his keys. At the first trial the lock responded; he grasped the door knob and silently and, with extreme caution, pushed open the door.

The hallway was unlighted. Sergeant Riley took out his flashlight and pressed the button on it for a second as he inspected the hall. He uttered a low grunt of satisfaction as he noted that there was a carpet on the floor, and also on the stairs leading to the second floor. That meant their footsteps would not be heard. He beckoned to the others to follow, and softly stepped inside.

Scarcely daring to breathe, the four raiders advanced. They made no noise on the thick carpet, but a collision with a piece of furniture or a false step might have ruined all their chances for success. Sergeant Riley was in the lead, quick flashes from his pocket torch showing the way.

After what seemed hours they reached the second floor. Thus far nothing had occurred to make them think that they had been discovered, but the hardest part was yet to come. From the third floor came the sound of voices and a shaft of light from an open door pierced the darkness of the hallway. The men above were talking in German.

There was a brief halt and then Sergeant Riley stole forward again. With breath in check and walking on tip-toe his three companions followed. The open door above was about five or six feet distant from the head of the stairs. They started up the last flight; the voices of the men above seemed raised in anger, and though Bob of course could not understand what was said, he thought that the tone of one of them sounded strangely familiar.

Suddenly the stairs under Sergeant Riley's foot creaked. The little band stopped short, their hearts pounding; every one gripped his revolver a bit tighter and waited for developments. Apparently the noise had not been heard, however, for the voices continued as before.

The advance was resumed and finally Sergeant Riley reached the top of the stairs. He went a little farther and took his stand just beside the opened door and barely out of the light. As the others came up they stationed themselves directly behind the sergeant and close against the wall.

It was a tense moment. Bob and Hugh could feel their hearts hammering so that it seemed to the two boys the noise must be heard. Their faces were pale, and frankly they were frightened. Suppose the men in the room should outnumber them and overpower them? Certainly if they were the spies and plotters they sought, they would be desperate. Then again it was just possible that the men were peaceful citizens, and that the affair would turn out to be a farce; that would be almost too humiliating.

Suddenly Sergeant Riley stepped forward into the open doorway.

"Hands up!" he ordered sharply, covering the inmates of the room with his pistol. His three companions crowded into the doorway alongside him.

There were three men seated about a table in the room, and they were completely taken by surprise. They started to their feet with muttered exclamations of anger and astonishment, staring with wide eyes at the four pistols levelled at them from the doorway.

One man hesitated and made a move as if to reach around towards his hip pocket, but Sergeant Riley was alert.

"None of that," he cried. "Put up your hands."

The man hastened to obey and together the three stood and faced their captors. Sullen and angry they looked, and not one of them spoke.

"Now, Marshal," said Sergeant Riley, speaking to the policeman next to him. "I wish you would be so good as to relieve these gentlemen of any hardware they may have concealed about them."

While Riley and Bob and Hugh covered the three prisoners, the officer went rapidly from one to another and took a revolver from each one of them. He also examined their other pockets, but finding no additional weapons returned to his post by the door.

While this little drama was being enacted Bob had a chance to look about the room. It was scantily furnished, a table, four chairs, and a shelf along the wall constituting its equipment. On the shelf were a dozen or more bottles that looked as if they might contain chemicals; a square black box stood on the table and also a brass spring and what resembled a cord hanging from one side. Bob decided it was a bomb. From a nail in the center of the ceiling a small alligator was suspended by its tail. Bob recognized the missing Percy, and decided that this must be the headquarters of the gang that had used an alligator as its symbol, and traced a picture of it on all the notes and warnings they sent out.

While the furnishings of the room were interesting, the three men captured were far more so, and as Bob saw one of them he experienced a distinct shock. The first was a man with dark hair, weighing perhaps one hundred and fifty pounds, and having a close-cropped mustache; the fake detective beyond a doubt. The second was a thin, wiry individual with a beard, and a swollen, red nose. He was the man who had escaped from his and Hugh's hands at the factory, Bob decided. His nose was swollen where Hugh had hit him. This must be the man who had set off the bomb.

The third prisoner was the one who furnished the surprise to Bob, however. He was a man Bob had known for years, and liked, admired, and trusted as well. He was Karl Hoffmann.

"Well," exclaimed Sergeant Riley, "it looks as if you men was through with your work. Get out your handcuffs, Marshal."

Up till now not one of the prisoners had spoken. When they saw the manacles being brought out, however, they shifted uneasily and Karl spoke.

"Bob," he said. "This is all a mistake."

Bob would have liked to believe him but before he had an opportunity to say anything Sergeant Riley spoke up. "Perhaps it is a mistake," he exclaimed. "We can talk that over down at the police station better than here, however."

There was now little left to do. The handcuffs were quickly attached to the prisoners' wrists and Hugh was sent to the second floor to telephone for the patrol wagon. The prisoners were marched downstairs, and Mr. Cook and the other policeman were summoned. Mr. Cook was as shocked as Bob had been to see Karl Hoffmann among those who had been captured in the raid.

There was nothing for it, however, but to see him loaded into the patrol wagon and driven away to police headquarters.



CHAPTER XXVIII

CONCLUSION

Mr. Cook, with Bob and Hugh, returned home. They had been in the house only a few moments when the telephone rang, and Mr. Cook answered it to find Sergeant Riley on the wire.

"I want to come up and see yez," he said. "I've let one of your friends out of jail and I'll bring him along with me if you don't mind."

He offered no further explanations, and the three friends were at a loss to understand what his visit could mean and who the "friend" might be.

"It must be Karl," said Mr. Cook. "No one can convince me he's disloyal."

"I guess that's who it is all right," agreed Bob.

They discussed their experiences of the past two days, but no one was able to offer any satisfactory explanation for the strange events through which they had passed. There was only one thing of which they were certain and that was that a band of men who were working for Germany had been plotting against the peace and welfare of the United States.

It was not long, however, before Sergeant Riley arrived and every one was greatly astonished to see that his companion was none other than Heinrich.

"Yes," said the sergeant. "Here's your friend Heinrich back again, and I guess he's here to stay this time."

Mr. Cook was a trifle cool in his greeting to the chauffeur. Not that he did not like him, but he had hoped to see Karl with the police sergeant. He had been convinced of Heinrich's guilt, while he had considered Karl to be innocent. Furthermore Karl had been foreman of the factory for a number of years and had proved himself a most intelligent and valuable workman.

"Heinrich has a story to tell you," said Sergeant Riley.

"You confessed, did you, Heinrich?" asked Mr. Cook. He was under the impression that he had confessed in order to save himself, and glad as he was to have the mystery and uncertainty ended he did not like a "tell-tale."

"He had nothing to confess," said Riley. "Tell your story, Heinrich."

"Well," began Heinrich nervously, "in the first place you all suspected me because I worked for Mr. Wernberg. Mr. Wernberg was working all the time for the United States."

"What?" exclaimed Mr. Cook in surprise.

"Yes," said Heinrich, "that iss what he was doing. He knew there was plots on foot and he knew every one in High Ridge was suspicious of him. He decided to expose those plots and prove that he was a good American. He hired Lena and me mit some others to help him."

"Lena, too, was all right?" demanded Bob.

"Certainly," exclaimed Heinrich. "Of course she iss all right. Mr. Wernberg he knew who these plotters were, but he was not able to prove anything about them. He also knew that they were meeting in that old house out in the woods. The night before last he went out there in a big gray roadster to search the house."

"I didn't know that was his car," said Bob in surprise.

"Yes," said Heinrich, "and I was mit him. You and Hugh followed us and we knew it, so to scare you away I took the automobile and brought it home. You see Mr. Wernberg wanted to do it all himself."

"We couldn't understand it," muttered Hugh. "To think that you were fooling us all the time, Heinie."

"Yes," grinned the chauffeur, "I fool you all right. Well that night we could not find anything so we left and Mr. Wernberg went back the next afternoon to look around. One of the plotter's gang discovered that he was there and tried to blow him up."

"But who locked us in that room?" demanded Bob.

"I did," said Heinrich. "I thought you was part of the German gang."

"Didn't you see us?"

"No, I only hear you talking. Then I fire one shot to give you a scare."

"And you almost blew Bob's head off," added Hugh.

"I tried to shoot high," said Heinrich. "Then I hurry away to tell Mr. Wernberg that I had two of the plotters caught. When I was gone I guess one of the plotters came there and you had a fight with him."

"The fake detective," exclaimed Bob.

"His name iss Kraus," said Heinrich. "He has a little mustache, and in the afternoon he blew up the house, because he knew we were after him and he wished to destroy all evidence."

"That's when Mr. Wernberg got hurt," said Mr. Cook. "What was he doing in the house, Heinrich?" He was amazed at the way the mystery was clearing itself up.

"As I told you," said Heinrich. "He was looking around for evidence against the gang."

"Why didn't he notify the police if he was suspicious?"

"As I told you," repeated Heinrich patiently, "he wished to do all himself and when he turned those men over to the police no one could say he was forced to do it. They sent him lots of warning notes because they knew he was after them."

"What did the alligator mean?"

"It iss the sign of a secret society; all Germans in High Ridge know that. It was that snake Hoffmann who stole poor Percy to kill him and hang him up in the room where they had their office."

"How long has Karl been a member of the gang?" asked Mr. Cook.

"Ever since Germany went to war with England," said Heinrich. "Nearly three years."

"But he never talked as though he sided with Germany."

"The ones who mean trouble never do," said Heinrich. "Karl knew enough to keep his mouth shut. You see you never suspected him."

"Tell me about Lena," exclaimed Mr. Cook. "Why was she meeting that man Kraus down town tonight and going around with him if she was not working with the gang?"

"She pretended to Karl Hoffmann that she was working mit them. All the time she was acting as a spy for Mr. Wernberg. Because Karl Hoffmann was in love with her he told her lots of things, and it was in that way we got most of our information."

"Pretty clever, eh?" exclaimed Sergeant Riley, approvingly.

"There's another thing, Heinrich," said Mr. Cook. "Why wouldn't you read what was written on that paper tonight?"

Heinrich looked sheepish. "I could not," he said. "Kraus had become suspicious of Lena; he feared she was going to betray them and the note was a warning to her. It said that if they were caught they would see to it that she went to jail mit them. At that time you were all suspecting poor Lena, and I was afraid you would send her to jail before she had a chance to prove to you that she was loyal."

"You're in love with Lena, aren't you?" asked Mr. Cook.

"We are to be married," said Heinrich, proudly, his eyes shining.

"Did Karl suspect that Lena was treacherous?"

"I think not until he saw that note."

"He was going to read it to us though."

"He would not have read it," cried Heinrich hotly. "He would have made up something, not what it said at all."

"Who shot Lena?"

"Kraus shot her. She was going to your office to warn you that your factory was going to be blown up, and he shot her to prevent that."

"Who was the man with the whiskers?" asked Bob.

"His name iss Mueller. He iss the one who set off the bomb tonight."

"That's what we thought," exclaimed Bob. "Well, Hugh, you hit him one good one anyway, didn't you?"

"I hope so," said Hugh.

"There was four of them altogether," said Heinrich. "Kraus, Mueller, Hoffmann, and a man named Schaefer who went to blow up the railroad bridge Friday night and has not been heard of since."

"We know where he is, don't we, Hugh?" laughed Bob.

"Where iss he?" demanded Heinrich.

"In jail, I guess," said Bob. "We caught him on the bridge with a bomb."

"Good boys," said Heinrich warmly.

"Why were you so angry when you had to go with father tonight?" asked Bob. "Where was your engagement?"

"I was going with Lena to twelve eighty-two Elm Street, where Schaefer lived. You see Lena was already a member of the gang, so they thought, and I was to join too, so we both could watch them better."

"Somebody telephoned Lena about meeting them there this evening."

"Yes, it was Mueller. He thought he had a recruit in me."

"Well, Heinrich," said Mr. Cook, "I guess that explains pretty nearly everything, and I'm sorry I ever suspected you." He shook hands warmly.

"Oh, that's all right," smiled Heinrich. "I had to get suspected with the job I had. That was part of the game."

At that moment the door bell rang and Dr. Clarke was ushered in. "I thought you might be interested in the hospital patients," he said. "Mr. Wernberg will recover all right, and Lena is not badly hurt. She keeps calling all the time for somebody named Heinrich. Do you know him?"

"Will you excuse me, Mr. Cook?" exclaimed Heinrich, and, without waiting for a reply, he dashed out of the room, nearly falling over two chairs in his haste to get away to the hospital.

"He seems to be in a hurry, doesn't he?" laughed the doctor.

"I must be going, too," said Sergeant Riley. "I have some boarders down at my hotel who may need attention."

"Well, good-night, Sergeant," exclaimed Mr. Cook, shaking hands with the doughty officer. "I'm sorry Hoffmann was mixed up in this business, but I'm glad it's all cleared up. I hope we'll have no more trouble."

"Ye won't, as long as yez have two young fellers like Bob and Hugh working for yez," exclaimed Riley. "The United States needs boys like that; this war is going to be a long and hard one in my opinion."

"I'm afraid so," Mr. Cook agreed. "I guess we'll come out all right if we all work hard and stick together though."

"That's it," exclaimed Riley. "We must all work together. Our personal feelings don't count. It's what our country needs."

He said good night all around and went out.

* * * * *

The next morning Bob was out in the yard inspecting a plot of ground where he was going to have a garden. He could not enlist, but he was going to "do his bit" by raising a few vegetables, and thus help to supply the country with its necessary food. He heard a step behind him and turned to see Frank Wernberg.

Frank held out his hand. "Shake hands with me, Bob," he exclaimed. "I want to tell you that I was wrong about that the other day, and you were right."

Bob responded heartily. "Yes," said Frank.

"I was dead wrong. I had thought from the way father talked that he was pro-German, but I found out that he wasn't at all. When it came to a question of deciding between his country and Germany there was never any doubt about where he stood."

"I know that, Frank," said Bob. "I wish every one of German birth or descent over here felt the same way."

"I think most of them do," said Frank.

"I guess that's right," Bob agreed. "Look at Lena and Heinrich."

"Well, all I wish now," exclaimed Frank, "is that we could enlist."

"So do I," cried Bob enthusiastically. "Wouldn't it be wonderful if you and Hugh and I could enlist and go together?"

The new adventures are recorded in the story entitled,

BOB COOK AND THE GERMAN AIR FLEET.

THE END