Sudden and unexpected was the knocking, and it found the boys unready to answer it. They had no idea that the conspirators—either or both of them—would come directly from their conference to the room where a watch had been kept on them.

"Do you think he saw us?" asked Joe, in a whisper.

"S'posing he did?" demanded Charlie. "We have the goods on him, all right."

Blake held up a hand to enjoin silence, though the remarks of his friends had been made in the lowest of tones.

The knock was given again, and the voice of the Frenchman asked:

"Are you within, my friends of the camera? I wish to speak with you!"

"One moment!" called Blake, in a tone he tried to make pleasant. Then he motioned to Joe and Charlie to seem to be busy over the midget camera, which was kept ready for instant use. At the same moment Blake threw a black focusing cloth over the mirror, for he thought the Frenchman might notice that it was in a position to reflect whatever took place in the opposite room.

"Act natural—as if you were getting ready to make some pictures," Blake whispered in Joe's ear, and then opened the door.

"Pardon me for disturbing you," began Lieutenant Secor, "but I have just come down from on deck. They are having a special lifeboat drill, and I thought perhaps you might like to get some views of it. Also, I have a favor to ask of you."

"Come in," said Blake, as he opened the door wider. At the same time he noticed that the door of the stateroom across the corridor was shut.

"Just came down from deck, did he?" mused Joe, as he took note of the Frenchman's false statement. "Well, he must have run up and run down again in jig fashion to be able to do that. I wonder what he wants to ask us?"

Joe and Charlie pretended to be adjusting the small camera, and Blake smiled a welcome he did not feel. Black suspicion was in his heart against the Frenchman. An open enemy Blake could understand, but not a spy or a traitor.

"I thought perhaps you might like to get some of the views from on deck," went on Lieutenant Secor, smiling his white-toothed smile. "They are even lowering boats into the water—a realistic drill!"

Blake looked at Joe as much as to ask if it would be advisable to get some views. At the same time Blake made a sign which Joe interpreted to mean:

"Go up on deck and see what's going on—you and Charlie. I'll take care of him down here."

"Come on!" Joe remarked to their helper, as he gathered up the small camera. "We'll take this in."

"I thought you might like it," said the Frenchman. "That's why I hurried down to tell you."

"Now I wonder," thought Blake to himself, as Joe made ready to leave, "why he thinks it worth his while to tell that untruth? What is his game?"

At the same time an uneasy thought came to Joe.

"If we go up and leave Blake alone with this fellow, may not something happen? Perhaps he'll attack Blake!"

But that thought no sooner came than it was dismissed, for, Joe reasoned, what harm could happen to his chum, who was well able to take care of himself? True, the Frenchman might be armed, but so was Blake. Then, too, there could be no object in attacking Blake. He had little of value on his person, and the films and cameras were not in the stateroom. And there were no films of any value as yet, either.

"Guess I'm doing too much imagining," said Joe to himself. "This fellow may be a plotter and a spy in German pay—and I haven't any doubt but what he is—but I reckon Blake can look after himself. Anyhow, he wants me to leave Secor to him, and I'll do it. But not too long!"

So Joe and Charlie, taking the small camera with them, went up on deck. There they did find an unusual lifeboat drill going on. The danger zone was now so close that Captain Merceau and his officers of the ship were taking no chances. They wanted to be prepared for the worst, and so they had the men passengers practise getting into the boats, which were lowered into the water and rowed a short distance away from the ship.

The women and children, of whom there were a few on board, watched from the decks, taking note of how to get into the boats, and how best to act once they were in their places.

"Going to film this?" asked Charlie of Joe.

"No, I think not," was the answer. "It's interesting, but there have been lots of drills like it. If it were the real thing, now, I'd shoot; but I'm going to save the film on the chance of getting a sub or a torpedo. This is a sort of bluff on the part of you and me, anyhow. Blake wanted to get us out of the cabin while he tackled Secor, I reckon. What his game is I don't know."

"I can come pretty near to guessing," said Macaroni, as he stretched his lank legs, which had, in part, earned him the nickname. "That fake lieutenant is planning some game with the German spy, that's his game."

"Maybe," admitted Joe. "But I don't see how we figure in it."

"Perhaps we will after we've gotten some reels of valuable film," suggested Charlie. "Don't crow until you've ground out the last bit of footage."

"No, that's right. Look, that boat's going to spill if I'm any judge!"

Excited shouts and a confusion of orders drew the attention of the boys and many others to a lifeboat where, amidships on the port side, it was being lowered away as part of the drill. There were a number of sailors in it—part of the crew—and, as Joe and Charlie watched, one of the falls became jammed with the result that the stern of the boat was suddenly lowered while the bow was held in place.

As might have been expected, the sudden tilting of the boat at an acute angle threw the occupants all into one end. There were yells and shouts, and then came splashes, as one after another fell into the ocean.Women and children screamed and men hoarsely called to one another. For a moment it looked as though the safety drill would result in a tragedy, and then shrill laughter from the men who had fallen into the water, as well as cries of merriment from those who still clung to the boat, showed that, if not intended as a joke, the happening had been turned into one.

The sailors were all good swimmers, the day was sunny and the water warm, and in a short time another boat had been rowed to the scene of the upset, and those who went overboard were picked up, still laughing.

"I might have taken that if I had known they were going to pull a stunt like that," said Joe, a bit regretfully. "However, I guess we'll get all the excitement we want when we get to the war front."

"I believe you!" exclaimed Charlie. "There's our German spy," he added, pointing to the dark-complexioned and bearded man who had been seen, through the mirrors' reflections, talking to the Frenchman. He had evidently hurried up on deck to ascertain the cause of the confusion, for he was without collar or tie.

The boat was righted, the wet sailors went laughing below to change into dry garments, and the passengers resumed their usual occupations which, in the main, consisted of nervously watching the heaving waves for a sight of a periscope, or a wake of bubbles that might tell of an on-speeding torpedo.

Mr. Labenstein, to credit him with the name on the passenger list, gave a look around, and, seeing that there was no danger, at once went below again.

"Wonder how Blake's making out?" asked Charlie of Joe, as they walked the deck. "Do you think we'd better go down?"

"Not until we get some word from him. Hello! Here he is now!" and Joe pointed to their friend coming toward them.

"Well?" asked Joe significantly.

"Nothing much," answered Blake. "He was as nice and affable as he always is. Just talked about the war in general terms. Said the Allies and Uncle Sam were sure to win."

"Did he want anything?" asked Charlie. "He said he was going to ask a favor, you know."

"Well, he hinted for information as to what we were going to do on the other side, but I didn't give him any satisfaction. Then he wanted to know whether we would consider an offer from the French Government."

"What'd you say to that?"

"I didn't give him a direct answer. Said I'd think about it. I thought it best to string him along. No telling what may be behind it all."

"You're right," agreed Joe. "Lieutenant Secor will bear watching. Did he have any idea we were observing him?"

"I think not. If he did, he didn't let on. But I thought sure, when he came across the corridor and knocked, that he'd discovered us."

"So did I, and I was all ready to bluff him out. But we'll have to be on the watch, and especially on the other side."

"What do you mean?" asked Blake.

"Well, I have an idea he's after our films, the same as he was before, either to spoil them or get them for some purpose of his own. Just now we aren't taking any, and he hasn't any desire, I suppose, to get possession of the unexposed reels. But when we begin to make pictures of our boys in the trenches, and perhaps of some engagements, we'll have to see that the reels are well guarded."

"We will," agreed Blake. "What was going on up here? We heard a racket, and Labenstein rushed up half dressed."

"Lifeboat spilled—no harm done," explained Charlie. "Well, I might as well take this camera below if we're not going to use it."

"Come on, Blake," urged Joe. "They're going to have gun drill. Let's watch."

The vessel carried four quick-firing guns for use against submarines, one each in the bow and stern, and one on either beam. The gunners were from Uncle Sam's navy and were expert marksmen, as had been evidenced in practice.

"Are we in the danger zone yet?" asked one of the two young women whose acquaintance Blake and Joe had made through the courtesy of Captain Merceau.

"Oh, yes," Blake answered. "We have been for some time."

"But I thought when we got there we would be protected by warships or torpedo-boat destroyers," said Miss Hanson.

"We're supposed to be," replied Joe. "I've been looking for a sight of one. They may be along any minute. Look, there comes a messenger from the wireless room. He's going to the bridge where the captain is. Maybe that's word from a destroyer now."

Interestedly they watched the messenger make his way to the bridge with a slip of paper in his hand. And then, before he could reach it, there came a hail from the lookout in the crow's nest high above the deck.

He called in French, but Joe and Blake knew what he said. It was:

"Periscope ahoy! Two points off on the port bow! Periscope ahoy!"