"You sneak!" yelled the stoop-shouldered one, making a rush at Mock and trying to seize the vial. But Mock dodged. In the same instant the bespectacled German tried to snatch the other vial away from Wilhelm, but that soldier, too, dodged and saved the vial. "On the ground is a good place for you!" growled Sergeant Kelly, knocking the stoop-shouldered stranger flat. Then, before the fellow could rise Kelly had snapped handcuffs his wrists. Two of the soldiers seized the bespectacled German just as he started to run. He, too, felt the clasp of steel around his wrists. Though Kelly and the four privates were armed with automatic pistols no weapon had been drawn. "Twice you've played the sneak, you!" hissed the stoop-shouldered one, glaring at Private Mock. "Twice more I'll do it to help Uncle Sam," retorted Mock, with a short laugh. "I owed it to you to see you caught!" "But you're a German!" hissed the bespectacled one at Wilhelm. "Why did you turn on us, who are also German?" "My father was a German; he's an American now," said Wilhelm, coolly. "Me, I've always been an American, and I'm one now, and will be as long as I live." "Let me have those vials," Dick ordered. "Sergeant, take these, and mark them as soon as you get back to company office. Then we'll turn them over to the medical department. Sergeant, march your prisoners." Heading toward the road Sergeant Kelly and his four soldiers led the German captives away. Captain Dick, with Mock and Wilhelm, followed, but did not attempt to keep up with the sergeant's party, When Kelly showed up in camp again he did not have his prisoners with him. He had taken them elsewhere, and they were soon on their way to an internment camp, where, like "good" Germans in America, they would live until the close of the war, cut off from all further chance to plot against Uncle Sam's soldiers. Halting at a farm-house on the way, Dick telephoned to regimental headquarters. Two minutes after his message had been received Private Brown, white-faced and haggard, was placed under arrest. Under grilling, he confessed what Secret Service men had already learned---that his name was really spelled B-r-a-u-n; that both he and his father were German subjects, and that the young man had enlisted for the sole purpose of playing the spy and the plotter in the Army. It had been Mock's talk of deserting in France that had caused Braun to talk to Mock, who had been told by Captain Prescott to talk in that vein while in the bull-pen. Braun had fallen into the trap. As for Wilhelm---which wasn't the young an's real name---he was the son of a German-born father, but a young man of known loyalty to the United States. He wasn't a soldier, but a War Department agent who had donned the uniform for a purpose, and had come to Camp Berry with a draft of real soldiers.