Wilbur went down heavily, the breath being driven from his body. His head struck against a table leg, so stunning him that it was an easy matter for Roger and Jimmy to leap on him and secure him. Roger, greatly exhausted, sat on Bixton's chest. "I--I'm all in! I quit!" the signal corps man gasped. "Let me get up!" "Not much!" panted Jimmy. "We've got you where we want you now. Lively, Roger. We've got to bind and gag these fellows." "What's the idea of gagging them?" "So they won't tell we're here." "Tell who we're here?" asked Roger, who did not get his chum's meaning. "The Germans who are coming here to carry out some secret pact. You know what we overheard these fellows saying. Well, now I'm going to hide here and see the show out when the Heinies arrive. We'll bind these fellows and hide 'em. Then we'll wait for Mr. Carl Anker and Mr. Fritz Ammann, whoever they may be." At the mention of these names Wilbur Bixton squirmed, and tried to shake off Roger. "That'll be about all from you!" cried Jimmy in anger. "Either you'll lie still, you dirty traitor, or we'll put an end to this right now! You tried to kill Roger and me, and we won't show you any more mercy than we would a wild beast. Now lie still!" He sprang up and took one of the two rifles. "It's all up!" said Wilbur, and his voice was hopeless. "You fellows win." "We haven't taken all the tricks yet," observed Jimmy grimly. "The game has only just started. Now, Roger, as soon as you get your breath, take off his uniform and slip it on yourself. I'll do the same for the other--dog!" he added contemptuously. "What's the idea of changing clothes?" asked Roger. "There are two ideas in this," answered Jimmy. "One is that our uniforms are wet and theirs are dry. Since they are to blame for the wet suits, it's only fair that they should wear 'em. But we won't take the trouble to re-dress 'em. Let 'em lie in their underclothes. It isn't cold in here." There was a sound from Aleck, which seemed to indicate that he was regaining consciousness. Jimmy quickly secured the other rifle, and then, having made sure that the Bixtons were unarmed, the work of changing uniforms was begun. While Jimmy stood on the alert with the rifle, Roger stripped off Wilbur's signal corps uniform. Then Roger changed down to his skin, wringing out his wet underwear and hanging it over a chair to dry. Next he donned the signal corps man's uniform without taking time to first clothe himself in undergarments. Wilbur was bound and gagged, being dragged to a dark corner of the cave. Then the same treatment was given Aleck, who came to his senses as he was being bound, and murmured: "Did we do 'em, Will?" "I'll answer for your brother," said Jimmy. "He's sort of incapacitated just now, as you'll be a little later. No, you didn't do for us, and you can't now. The jig is up for you fellows."