But the Army Boy's plan for an immediate further investigation of the mysterious alley was destined to have a further setback, for the next day great aeroplane activity started all over the American front, and it was announced that nobody would be given leave to visit Coblenz until further notice. It seemed that reports had been received at general headquarters that the rioters, driven out of Coblenz, were gathering in smaller towns throughout the occupied area, and making demonstrations and inflammatory speeches against the American "invaders." Many aviators were detailed to fly over all the neighboring territory and get information of the movements and numbers of the rioters, so that troops could be sent to the threatened points and suppress the uprisings before they assumed serious proportions. Among the aviators detailed to this work was Dick Lever, and on his return from one of these excursions he sought out his Army Boy friends. For a considerable time he had been detailed to other parts of the occupied territory, but now his headquarters were temporarily near the barracks in which the boys were situated. So it happened that one evening as Frank, Bart, and Billy were strolling toward the canteen, they were both surprised and delighted to espy the long, athletic figure of their friend. Dick was no less glad to see them, and everybody for some distance around was apprised of the fact that old comrades had met once more. "But where's Tom?" inquired Dick, after the first burst of enthusiasm was over. "I'm so used to seeing you fellows as a quartette that your sweet voices don't sound exactly correct as a trio." The faces of all the boys lengthened at this allusion to their missing friend, and in a few words they explained to Dick the circumstances of his sudden disappearance. "By Jove!" exclaimed Dick excitedly, when they had finished, "I wouldn't be a bit surprised if I could put you on his trail." "What do you mean?" chorused the boys. "Now, don't get excited," said Dick. "What I'm going to tell you may not be of the least importance after all. It's just this. While I was reconnoitering over the various camps of the revolutionists, in one of them I was sure I saw a man in an American Army uniform. I was too far up to recognize him even if I had known him, and it might be any American prisoner other than Tom, or it might be a German dressed in an American uniform for spying purposes. Anyway, if I hadn't been under special rush orders to return as soon as possible, I would have gone down and maybe attempted a rescue, but I had to get back immediately with my information, so couldn't take any chances." "But can you give us any idea of the direction of the camp where you saw this man?" inquired Frank. "If we had the least idea where to look for him, you can bet we'd get him away from those renegade Germans, and likely hurt anybody that got in the way, too."