How long they lay entombed in the German tunnel the moving picture boys did not know. They must have been unconscious for some time.
Joe was the first to regain his senses. Telling about it later, he said he dreamed that he had been taking views in Earthquake Land and that, somehow or other, a volcano had fallen on his chest. He had difficulty in breathing, and no wonder, for as he came to his senses he found that a great rock and a pile of earth were across him.
Slowly at first, fearing to move much because he might bring down more débris on himself, Joe felt about. He found that his arms and hands were comparatively free, though partly buried in earth.
"I say!" he called, and his voice sounded strange in that dark and broken tunnel, "is any one here but me? Blake! Charlie! Are you alive?"
No one answered, and then, feeling his strength coming back, Joe ventured to move. He found that he could manage to emerge from the pile of earth and stones that had fallen on him, fortunately none over his head. When he ventured to stand upright he tried to pierce the darkness and find out what had become of his chums.
But he could see nothing until he thought of his pocket lamp and, taking it in his hand, flashed it about him. The light revealed to him the figures of Blake and Charlie, lying not far away and covered with débris as he had been.
He set the little light on a rock, leaving the switch on, and by the intense but limited glow, he set to work to free his companions. Blake's head was bleeding from the cut of a sharp rock, but he, like Joe and Charlie, had fallen in such a way, or rather, the cave-in had taken place in such a manner, that their heads and faces were comparatively free from dirt, else they would have been smothered.
Joe worked feverishly to free his chums and at length succeeded in freeing his assistant, who, of the two, was less covered by the débris. Charlie opened his eyes and looked about him, asking:
"What happened? Where am I?"
"Don't stop to ask questions now," directed Joe. "Help me with Blake. I'm afraid he's hurt!"
The two together got their chum cleared of the débris finally, and then Joe, taking a flask of cold coffee from his pocket, gave his now half-unconscious chum some to drink. This served further to rouse Blake, and it was soon found, aside from a painful cut on the head, that he was uninjured except for bruises, such as they all had.
"But what happened?" asked Charlie, as they sat down to rest on some rocks and took turns finishing Joe's limited supply of coffee.
"The tunnel caved in on us after a big explosion of some kind," Joe said. "I guess we're going to have trouble getting out, too."
"Let's have a look," suggested Blake. "We can't stay in here much longer or more of the roof and sides may cave in. Can we get out?"
"I haven't looked," answered Joe. "I wanted to get the dirt off you fellows. I'm afraid we're caught, though."
And they were. An examination, made with the pocket lights, showed them that the way back was blocked by a mass of rock and earth and that no progress ahead could be made for the same reason.
"I guess we'll have to dig our way out," said Joe.
"What with?" asked Charlie.
"Some of the broken boards that held up the tunnel," was the answer, and Joe pointed to pieces of timber that had been splintered and shattered by the cave-in.
"Yes, it's the only way out," agreed Blake, who, now that his cut had been bound up with bandages from the first-aid kits the boys carried, felt better. "We'll have to dig out." And after a short rest they began this work.
A terrible fear was upon them, a fear greater than that caused by their capture by the Germans with the possibility of being shot as spies. It was the fear of a horrible death—buried alive.
They dug as best they could for some time with the broken boards, their hands becoming cut and bruised by the rough edges. And yet, with all their efforts, they could not see that they had gained much.
They were digging back along the way they had come in, for, as Blake said, they knew how long the tunnel was in that direction, but they did not know how far it extended the other way.
"Is it of any use to continue?" asked Joe wearily, when they had been digging for what seemed several hours, though really it was not as long as that.
"Of course we've got to continue!" declared Blake, half savagely. "We can't give up now—and die!"
"We may die anyhow," said Joe.
They were resting in the darkness after strenuous digging. In the dark because, to save the battery, they had switched off the electric light by which they had been working.
Charlie turned to look back. They had been piling the earth behind them as they worked, but there was not much of it as yet. They had made but small impression on the débris that hemmed them in. And as Charlie looked he uttered a cry.
"What is it?" asked Blake.
"A light! Don't you see a light there?" Charlie demanded. "See! Back there through the chinks in the rock. See, a flickering light!"
There was no doubt of it! There was a gleam of light, and it appeared to come from a point where some fallen rocks were loosely piled.
Dropping their boards, which they had been using for shovels, the boys climbed as near as they could to the hole. In the dark as they were, the light showed plainly.
"Can you see anything?" asked Charlie of Joe, who was nearest.
"No, only some figures moving about. It seems like some sort of dugout beyond there, and it hasn't caved in. Maybe it's the end of the tunnel."
"Did you say you can see somebody in there?" asked Blake.
"Yes; figures moving about."
"Call to them."
"Maybe they're Germans!" exclaimed Charlie.
"They probably are," Blake answered. "But we've got to be rescued from here and take our chance with them. It's better than being buried alive. Hello, there!" he shouted. "Help us get out!" and he began tearing at the stones with his hands.
Seeing his object, his chums helped him. And then some one on the other side of the rocky barrier also began pulling down the stones, so that in a little while, the light becoming momentarily greater, the boys saw a way of escape open to them.
But it was a strange way. For when the rocks had been pulled down sufficiently to enable them to crawl through, they emerged into a space—a small room, as it were—walled with solid logs. Logs also formed the roof. It was a room lighted by a lantern, and on a pile of bags in one corner lay a huddled figure of a man. Standing near him was another man—a man in a ragged blue uniform—and at the sight of his face Blake murmured:
"At your service!" said the Frenchman, bowing slightly.
"No!" bitterly cried Blake. "Not at our service—you traitor!"
The Frenchman seemed to wince, but at that moment a call from the huddled man in the corner attracted his attention. He bent over him, drew back the covering and revealed in the lantern's glow the face of Labenstein.
The German raised himself on one elbow, and a wild look came over his face. His eyes gleamed brightly for a moment.
"They—they here!" he murmured. "Well, perhaps it is better so."
"How better? What does he mean?" asked Blake. "Does he think——"
"Hush!" and the Frenchman spoke softly. "This is the end—of Labenstein!" And even as he spoke the man fell back dead.
Lieutenant Secor seemed to breathe a sigh of relief, as though the death of the other had brought a great release to him.
"Now I can speak," said the officer. "Now I can explain, and perhaps you will again regard me as a friend," he said softly.
"Well," returned Blake, "you probably saved our lives by helping us get out of the tunnel. But as for being friends with——"
"Please do not say it," begged the lieutenant. "I have had to play a part. It is over now. I can again take my place with my comrades and fight openly for France. For I have learned all his secrets and whence the spy-leaks came. Now my unpleasant mission is over!"
"What—what do you mean?" asked Joe, beginning, as did his chums, to have an inkling of the truth. "Aren't you two working together against us and for Germany?"
"Never I!" cried the Frenchman. "I am a member of the French Secret Service, and for months I have consorted with that dog!" and he pointed at the dead man. "I but played a part to gain his confidence and to learn from what sources Germany was getting her secret information about our soldiers and yours. Now I know. I will explain. But come, we must get out of here."
"Can we get out?" asked Blake.
"Surely, yes. The tunnel goes from here into the German trenches, and the other end was not damaged by the explosion."
"But," exclaimed Joe, "the German trenches! We don't want to go there to be captured again."
"Have no fear," said the Frenchman, with a smile. "I should, perhaps, have said what were the German trenches. They are now held by some of your own troops—the brave Americans!"
"They are?" cried Charlie.
"That is true! You shall see!"
"Hurrah!" cried the moving picture boys, and their fears and weariness seemed to depart from them in a moment.
"The great airship raid was a success," went on the Frenchman. "Our troops and yours have made a big advance, and have captured many prisoners. They would have had Labenstein, but he is beyond prisons now. Let us go hence! Even dead I can not endure his company. I suffered much on his account."
"Well, things are happening so fast I don't know which to begin to think of first," remarked Joe. "But, on general principles, I presume it's a good thing to get out of this tunnel. Come on, boys."
"One moment," interposed the lieutenant. "Perhaps you will like to take these with you."
He stooped and lifted a pile of trench bags, and the boys saw the boxes of moving picture films.
"Ours?" cried Joe.
"None else," answered the Frenchman. "I trust you will find them all right."
"Not a seal broken!" reported Charlie, who had quickly examined the cases. "This is great!"
Together, hardly able to believe their good luck, they made their way out of the log-protected room—once a German bomb-proof dugout. As they emerged into the trenches, carrying the films, the boys saw American soldiers.
"The Stars and Stripes!" cried Charlie, as he noted the United States flag. "Now we're all right!"
"Whew! We did make some advance!" added Blake, as they saw how the battle lines of the French and Americans had been extended since they had crawled into No Man's Land the night before.
The boys learned later that the airship raid was the forerunner of a big offensive that had been carried out when they were held prisoners and in the tunnel. The Germans had been driven back with heavy loss, and one of their ammunition dumps, or storage places, had been blown up, which had caused the collapse of the tunnel.
That the moving picture boys were welcomed by the soldiers, among whom they had many friends, goes without saying. And the recovery of the films was a matter for congratulation, for they were considered very valuable to the army.
"Though it was Lieutenant Secor who really saved them for us," explained Blake, when the story of their adventure was being told.
"And I am glad the time has come when Lieutenant Secor can appear in his true light," said Captain Black. "Even I suspected him, and he lost many friends who will come back to him, now that he risked all to serve his country in a rôle seldom honored—that of getting secret intelligence from the enemy."
For that is what the French lieutenant had been doing. Even while he was in the United States, where the boys first met him, he had been playing that part.
"But I assure you," he said to Blake and the others, "that the destruction of your films by my auto was an accident. When I found you believed it done purposely I let it go that way, as it helped me play my part the better. Also, I had to act in a manner to make you believe I was a friend of Labenstein. But that was all a part."
And it had not been an easy part for the French officer to play. He had, in ways of his own, come to suspect Labenstein, who went under various names, sometimes that of Karl Kooder. This man, who held forged citizenship papers of the United States, was a German spy and had done much to aid the Kaiser. But he accepted Lieutenant Secor as a co-worker, on the latter's representation that he, too, was a friend of Germany, or rather, as the Frenchman made Labenstein think, was willing to become so for a sum of money. So the two seemingly worked together.
"And it was thus you knew us," said the lieutenant to the boys. "Labenstein, to use one of his names, had orders to make all the trouble he could for you when you reached France, and to prevent your getting any pictures, if possible. Of course he could not do that, but he tried, even to the extent of writing a false note in London that caused your arrest. I had, seemingly, to help him, but all the while I was endeavoring to find out where the leak was on our side that enabled him to profit. And I found out. The leak will be stopped.
"I even seemed to join Labenstein in signaling the submarine, though that night, had he really succeeded in calling her with your light, I would have killed him where he stood. However, the depth charge solved that question.
"I had to escape from the ship with him to lull his suspicions against me. Then I went into the German ranks with him, being thought a deserter! That was hard for me, but I had my duty to perform.
"The rest you know. It was by a mere chance that Labenstein, when I was with him, came upon your films after the gas attack. He thought to profit personally from selling them, which is why he did not turn them over at once to his superiors. Ever since then he has been trying to dispose of them to enrich himself. And I have been trying to find a way to get them back to you without betraying myself and my mission.
"At last chance favored me. The big air attack came just after I had secured all the information I wanted. I was about to go back to my comrades and arrange for the capture of Labenstein if I could. He still had the films and was about to sell them to another German—a traitor like himself.
"Then came the big explosion, and he was fatally hurt. We both took refuge in the tunnel, Labenstein carrying with him the films, and you came just as Labenstein died. Well, perhaps it is better so."
"Yes," agreed Blake, "I think it is."
"And we have the films back!" exulted Charlie.
"But, best of all, we know Lieutenant Secor is straight!" cried Joe. "I'd hate to think anything else of him, after he saved our lives."
"Yes," agreed Blake softly.
"And now to get back on the job!" cried Joe, after a moment of silence.
And so the moving picture boys again took up their perilous calling. They soon recovered from their slight injuries caused by the cave-in of the tunnel, and, finding their cameras where they had left them in the French house, resumed the turning of the cranks.
They filmed many stirring scenes, and the records they made now form an important part of the archives of the War Office in Washington, the films so strangely lost and recovered being considered most valuable.
Lieutenant Secor became one of the boys' firmest friends, and through his help they were enabled to obtain many rare views. And now, having seen them safely through some of their perils, we will take leave of them.