CHAPTER

I THE FLASH FROM THE GUNS

II WRAPPED IN MYSTERY

III CAUGHT IN A STORM

IV THE RUINED CASTLE

V CONSPIRATORS

VI THE BAFFLED PLOTTERS

VII A CLOSE CALL

VIII JUST IN TIME

IX THE COLONEL'S WARNING

X FROM THE SKY

XI MARSHAL FOCH AND GENERAL PERSHING

XII TORN FROM MOORINGS

XIII GERMAN RIOTING

XIV ON THE TRAIL

XV A BARE CHANCE

XVI RAISING THE TRAP DOOR

XVII A PERILOUS SITUATION

XVIII THE CRITICAL MOMENT

XIX TURNING THE TABLES

XX THE CLAWS OF THE HUNS

XXI SQUARING ACCOUNTS

XXII WILL THE GERMANS SIGN?

XXIII ON THE VERGE OF DISCOVERY

XXIV THE DEADLY PHIAL

XXV THE TREATY SIGNED

CHAPTER I

THE FLASH FROM THE GUNS

"I tell you, Bart, I don't like the looks of things," remarked Frank Sheldon to his chum, Bart Raymond, as the two stood on a corner in the German city of Coblenz on the Rhine.

"What's on your mind?" inquired Bart, as he drew the collar of his raincoat more snugly around his neck and turned his back to the sleet-laden wind that was fairly blowing a gale. "I don't see anything to get stirred up about except this abominable weather. It's all I can do to keep my feet."

"It is a pretty tough night to be out on patrol duty," agreed Frank. "But it wasn't that I was thinking about. It's the way these Huns have been acting lately."

"Are you thinking of that sergeant of ours that was found stabbed to death the other night?" asked Bart, with quickened interest.

"Not so much that," replied Frank, "although that's one of the things that shows the way the wind is blowing. But it's the surly way the whole population is acting. Haven't you noticed it?"

"There certainly is a difference," admitted Bart. "Everything was peaches and cream when we first came. The people fairly fell over themselves in trying to tell us how glad they were to have the Americans here instead of the French and English. Now they're getting chesty again. A couple of fellows passed me a little while ago who looked at me as if they'd like to slip a knife into me if they dared."

"They hate us all right," declared Frank. "It makes them sore as the mischief to have Americans keeping the watch on the Rhine. They're mad enough to bite nails every time they're reminded of it."

"And that's pretty often," laughed Bart, "for they can't go out into the street without seeing an American uniform somewhere. We've got this old town pretty well policed, and if any trouble starts we'll put it down in a jiffy."

"Well, trouble's coming all right," prophesied Frank. "There are lots of new faces in the city, fellows who seem to have come from the outside. You know Germany's being ripped up the back everywhere by mobs, and the red flag is flying in Berlin. I have a hunch that these outsiders have come to start the same thing here."

"If they do they'll get more than they bargained for," said Bart grimly. "They'll find they're monkeying with a buzz saw. What our fellows would do to them would be a sin and a shame. But here come Tom and Billy, if I'm any sort of a guesser."

"Right you are," replied Frank, as he descried two uniformed figures approaching, their heads bent away from the icy gale which was increasing in fury as the night wore on.

"Hello, fellows," was the greeting that came from one of the newcomers, as they came into the flickering light of the street lamp, near which Frank Sheldon and Bart Raymond were standing. "This is a dandy night to be out patrolling—I don't think."

"A good night for ducks, Tom," replied Frank with a laugh.

"For polar bears, if you ask me," put in Billy Waldon, Tom's companion, as he shook the drops from his raincoat. "How would it be to be back in the barracks just now lapping up a smoking hot cup of coffee? Oh, boy!"

"It wouldn't be bad—" Bart was beginning, when suddenly a rifle cracked and a bullet whizzed by so close that it nearly grazed Tom Bradford's ear.

"Shelter, fellows!" shouted Frank, as he leaped for an adjacent hallway.

His companions followed him quickly, and crouching in the hall, they peered out into the darkness to see if they could detect the whereabouts of the would-be assassin.

But everything was quiet except for the roaring of the gale, and the street seemed to be empty.

"Might as well look for a needle in a haystack," muttered Tom Bradford. "We don't even know the direction from which the shot came. You can bet that skunk made tracks as soon as he fired."

"It was a mighty close call for you, Tom," remarked Billy. "A half inch closer and you would have been a goner."

"It would have been hard luck to have been laid out now after having come through that Argonne fighting alive," grumbled Tom. "I'd just like to have my hands right now on the cowardly Heinie who tried to snuff me out."

"Don't you see, Bart, that I was right when I told you that trouble was brewing?" remarked Frank.

"I guess you were, old man."

"It's because we've been too confoundedly easy with these fellows," snorted Billy wrathfully. "We've gone on the theory that if we treated 'em white and gave 'em a square deal they'd appreciate it and behave themselves. We might have known better."

"The French and English know these ginks better than we do, and they've put the boots into them from the start," growled Tom. "There's been no namby-pamby dealing with the Huns in the bridge- heads where they've held control. They've made the Boches walk Spanish. If they didn't uncover when the flag went by, they knocked their hats off for them. They know that the only argument that a Hun understands is force, and they've gone on that theory right along. And as a consequence the Heinies don't dare to peep in the districts where the French and English run things. We ought to take a leaf from their books and do the same."

"That's our good-natured American way of doing things," said Bart. "But we're due to stiffen up a bit now. We're not going to stand for attempts to murder in cold blood—"

He was interrupted by an exclamation from Frank.

"Quiet, fellows," he adjured in a low voice.

"See anything?" whispered Bart, who was nearest him.

"I thought I caught a glimpse of a fellow stealing into that alley half-way down the block," returned Frank. "And there goes another one," he added, with a trace of excitement in his voice.

"I was looking that way and I didn't see anything," murmured Billy Waldon rather incredulously.

"I'd bank on Frank," returned Bart. "He has the best eyes of any of us. They're regular telescopes."

"There goes another!" exclaimed Frank tensely. "There's something doing there, sure as guns!"

"I know that alley," said Tom Bradford. "I've often looked into it when I passed it on my beat. But it's a blind alley and doesn't lead to any thing. It ends at a brick wall."

"All the better chance to bag them," replied Frank. "We'll wait just a minute longer to see If any one else goes in, and then we'll go down and nip the whole bunch. It's against regulations for them to be on the streets at this hour, and you can bet they're up to no good."

"I only hope the fellow's among them that fired that shot," murmured Tom vengefully.

They waited a moment or two longer, but Frank Sheldon's eyes detected no other skulking figure and he gave the word to move.

"Have your clubs and pistols ready, but don't use the guns unless you have to," he ordered, for when the Army Boys were together the leadership by common consent devolved on Frank. "I guess the clubs will do the business if it comes to any resistance on their part."

"Fists would be enough," muttered Tom, as with the others he prepared to follow their leader.

Like so many ghosts they drifted out of the hallway, and, moving in the shadow of the houses, though in the rain and darkness that seemed almost unnecessary, they stealthily approached the entrance to the alley.

It was in one of the poorer sections of the town, and the dwelling houses were interspersed with factories and coal yards. On each side of the alley stood the wall of a factory, three stories in height. No light came from any window, and the alley itself was as dark as pitch.

"Bart and I will stand on this side, and you two fellows take the other side," whispered Frank, when they reached the mouth of the alley. "Keep right on your toes and be ready to nab those fellows when they come out."

The others did as directed and all waited, tense with expectation, their clubs ready for instant service if resistance should be offered.

The rain kept pouring down in torrents, and as it fell, a glaze formed on the sidewalks, so that it was with difficulty that the Army Boys kept their feet.

They were eager to bring the matter to a head, and the waiting in drenching rain wore on their patience.

"Could they have possibly gone out some other way, leaving us here to hold the bag?" queried Bart Raymond, after five minutes had passed without result.

"I don't think so," returned Frank. "I'm dead sure there isn't any way to get out except the way they went in. They're in there holding a pow-wow of some kind."

Ten minutes more passed, and by that time even Frank had begun to have doubts. Tom slipped over to him from the other side of the alley.

"For the love of Mike! let's get a move on and go into the alley and smoke them out," he whispered. "We can get them there just as well as here."

"Just five minutes more," Frank replied. "They may hear us going in and be on their guard, while if we nab them here we'll catch them unawares. But if they're not out in that time, we'll go in and round them up."

At the end of the stipulated time Frank gave the signal.

"Creep in as softly as you can," he admonished his comrades. "Spread across so that they can't slip between us. They've got to be somewhere between us and that brick wall at the back."

Moving with all the caution that their experience as scouts had taught them in their frequent incursions into No Man's Land during the war, the four Army Boys crept noiselessly into the darkness of the alley.

Ten, twenty, thirty feet, and still no sign of their quarry. They must be close to them now.

On they went, wonder gradually giving way to doubt, until with a muttered exclamation Frank came plump up against the wall that marked the alley's end.

"Stung!" he murmured in profound disgust.

His comrades gathered close about him.

"That's one on us," muttered Tom.

"We're done good and proper," agreed Billy.

"Are you dead sure that you saw them come in?" queried Bart of Frank.

"I know I did," replied Frank, who although puzzled was not shaken in his conviction.

"They must have been ghosts then," gibed Tom. "Nothing else could have vanished through a brick wall."

Frank drew his flashlight from his pocket and flashed it about. There was no one to be seen.

"That wall is perfectly blank," he murmured in perplexity. "Thirty feet high if it's an inch. There isn't an opening in it anywhere."

"Could they have got into the windows of the building on either side?" suggested Bart.

Frank swept the flashlight on the walls of the factories.

"Not a chance," he affirmed. "All these windows are protected with iron bars and nothing could get between them. Those fellows seem to have just melted away."

At that instant a report rang out, and the flashlight was knocked from his hand by a bullet.

"Down, fellows!" he shouted, setting the example, and the next moment all four were lying flat on the ground.

They were just in time, for there was a crackling of guns, and other bullets sped over their heads.

"After them, boys!" yelled Frank, leaping to his feet. "They're at the mouth of the alley. I saw the flash from their guns."

He sped for the street with his comrades close upon his heels, their pistols drawn and ready for instant use.

CHAPTER II

WRAPPED IN MYSTERY

The Army Boys looked eagerly about them when they reached the street, but could see no one. It was as though the earth had opened and swallowed the men who had sought their lives.

They scattered and ran in every direction, searching all hallways and side streets for blocks around, but nothing rewarded their endeavors, and it was a bedraggled and exasperated quartette that finally came together again to compare notes and report failure.

"Never saw anything like it in my life!" snorted Tom. "It's as though we were all bewitched. Somebody's wished a jinx on us. Some ghosts are putting up a job on us."

"There was nothing ghostly about that bullet that knocked the flashlight out of my hand or those other bullets that came singing over our heads while we were hugging the ground," said Frank grimly. "If I don't get to the bottom of this, you can call me a Chinaman."

"It gets my goat to think of those Heinies chuckling to themselves because they put one over on us," gritted Billy between his teeth.

"They laugh best who laugh last," growled Bart. "They'll laugh on the other side of their mouth when we lay hands on them."

"If we ever do," muttered pessimistic Tom. "But here comes our relief," he continued, as the light of a lantern hanging on the arm of the foremost man revealed a group coming toward them. "High time, too! I got drenched to the skin while I was lying on the ground in that alley."

"Of course we'll have to report the whole thing to the corporal, shan't we?" inquired Bart.

"I suppose we shall," Frank acquiesced, though reluctantly. "Personally, I'd like to keep the whole thing up my sleeve until we've solved the mystery. But there's danger abroad to-night, and it wouldn't be fair to the boys who are going to take our places not to put them on their guard."

The corporal of the guard now had come so close that the light of his lantern fell upon the group of Army Boys.

"You fellows are all here, I see," said the corporal, who was the boys' old friend, Wilson. "What was that shooting going on here? None of you hurt, I hope."

"Dripping wet but right as a trivet," Frank replied with a smile, and then went on to make his report of the occurrences of the night while the corporal listened with close attention.

"It's certainly strange," he commented when Frank had finished. "It's one of many queer things that are happening lately. I'll report the facts at headquarters and you may be called upon to tell your story there. But now you are off duty, and you can light out for the barracks."

They were only too glad to avail themselves of the permission, and hurried off.

"I've got an idea!" exclaimed Frank, as they scurried along before the gale.

"Frank's got an idea," chaffed Billy. "Hold on to it, old man, for dear life." Frank made a playful pass at him which Billy ducked.

"I've been figuring the thing out," went on Frank, "and I've come to the conclusion that those fellows wanted us to see them go into that alley."

There was an exclamation of surprise from his comrades.

"Come again," said Billy. "I don't get you."

"Why should they want us to see them?" queried Bart. "They might have known that we'd go in after them."

"Sure they did!" answered Frank. "That's just what they wanted. They figured that they'd get us all in there in a bunch. They guessed too that, not finding them, we'd flash a light. That would make us a good target to their confederates who had come to the mouth of the alley, and they thought they could mow us down with one volley. In other words the alley was a trap."

"By ginger, I believe you're right!" exclaimed Bart "The shots came just after the light was flashed. It was a slick trick. You have to hand it to them."

"But that doesn't explain where the men disappeared to who went into the alley first," remarked Billy.

"No," admitted Frank. "And it doesn't explain either where the men who fired the shots vanished to. But there's an answer to everything, and I'm going to try to find the answer to this. I'm not going to drop it. Of course, I suppose the secret service men will take the thing up, but I'm going to do a little investigating on my own account. I have a hunch that when I take a look at that alley by daylight, I'll tumble to something."

And while the four chums, after their narrow escape, are cudgeling their brains to solve the mystery, it may be well for the sake of those who have not read the preceding volumes of this series to trace briefly their adventures before this story opens.

Frank Sheldon, a vigorous, clean-cut, young fellow, was a resident of Camport, a thriving and prosperous town of about twenty-five thousand people. His father had died a few years before the war broke out, and Frank lived in a little cottage with his mother, of whom for some years he was the sole support. She was of French birth, and by the death of her father had recently come into possession of a considerable estate in France. There had been some legal complications regarding the settlement of the property, and she had intended to go to France to look after her interests when the outbreak of the war made this impossible.

Frank was employed in the wholesale hardware house of Moore and Thomas, and his prospects for the future were very bright when the United States entered the World War. Frank was above everything else a hundred-per-cent American, and if he had consulted only his own wishes would have enlisted at once. But his mother's dependence upon him made him hesitate. An episode occurred, however, that decided him, when he was forced to knock down a burly German who had insulted the American flag. There was no further opposition by his mother, and he joined the Thirty-seventh Regiment, a Camport regiment with a glorious record in the Civil War, and one which had recently seen service on the Mexican border.

Billy Waldon, a close friend of Frank, was already a member, and Bart Raymond, Frank's special chum and a fellow employee, joined also. Another friend, Tom Bradford, tried to join, but was rejected on account of his teeth. He was afterward accepted in the draft, however, so that the four chums, to their great joy, found themselves together in the same regiment.

There was one man in the Moore and Thomas firm who was a bitter and malignant anti-American from the start. His name was Nick Rabig, and he was foreman of one of the departments. He was born in America, but his parents were German. Rabig and Frank Sheldon were at sword's points most of the time because of the former's bullying disposition, and after Rabig had been caught in the draft and forced into the ranks of the old Thirty-seventh he got from Frank the thorough thrashing which had been for a long time coming to him.

What experiences the Army Boys went through in the training camps, how narrowly they escaped a submarine attack on the way to Europe, what exciting adventures they met with on their first contact with the enemy, are described in the first volume of the series entitled: "Army Boys in France; Or, From Training Camp to Trenches."

After they had once reached the scene of action the adventures of the Army Boys multiplied rapidly. Trench warfare was soon outgrown, and open fighting in the field became the order of the day. At one time when the American troops were advancing, the boys became separated from their comrades and were compelled to leap from a broken bridge into a stream, and when they attempted to swim to the other side found themselves in the enemy's hands. For a time a German prison camp with all its horrors loomed up before them, but from this they were saved by a friend of theirs, Dick Lever, who swooped down in his airplane, scattered the enemy guards, and carried his friends back in safety to their own lines.

Frank had the good luck to hear encouraging news about his mother's property from a French colonel whose life he had saved under a rain of fire when the officer, Colonel Pavet, was lying wounded on the battlefield.

Soon, from raw recruits the boys had been developed into skillful soldiers, as is shown in the second volume of the series, entitled: "Army Boys in the French Trenches; Or, Hand to Hand Fights with the Enemy."