"I give it up--at least for the present," said Jimmy. "It's another puzzle--like the time when we saw Captain Frank Dickerson at the red mill, maybe." "They could be French refugees," went on Roger. "Maybe they have been held prisoners by the Germans, and just got away." "Well, that's a possibility, of course," assented his chum. "But they don't look as if they had been in prison. They're too well dressed, and they look too well fed for that. In fact they look more like Germans than Frenchmen." "They do," assented Roger, as he peered over his friend's shoulder. "Still you can't always tell. At one time we thought Captain Dickerson looked like a German, but he wasn't. But the fact that these men are in civilian clothes is what gets me. They haven't any right so far inside our lines dressed like that." "You're right," said Jimmy. "There's some sort of a mystery here. It may turn out all right, and it may be all wrong. I'm going to----" Jimmy interrupted himself to utter an exclamation of surprise, for suddenly one of the men leaned over the table and blew out the candle, leaving the dugout in darkness. And, almost as if this was a signal of some sort, there began a furious bombardment, the echoes of which came to the ears of the Khaki Boys. "They're at it again!" cried Roger. "Those are our guns!" declared Jimmy. "We're paying the Huns back for smashing our fine dugout!" "The one we took from the Germans," added his chum. "Say, Jimmy," he went on. "You know all this around here used to be within the German lines; this tunnel and the dugouts." "Of course I know it," returned Jimmy. "What of it?" "Well, maybe there's a secret passage leading over to their new lines and trenches from here. Maybe that's how those two civilians got in here." "Nothing like that!" declared Jimmy. "The German lines are too far away from here now. Besides, why would two lone Germans venture back in the enemy's camp? It isn't reasonable." "Well, there's something queer," declared Roger, "and we'd better report it." "I guess so," agreed the young sergeant. "But now what shall we do--go ahead or wait here?" "Let's show a light and go on," decided Roger, for they had darkened their flash torches on seeing the burning candle. They had stood in the darkness while looking into the dugout containing the four men. Jimmy hesitated a moment. He did not at all like the situation. It was "extremely ticklish," he said afterward. To show a light now, when the four men were in darkness, would mean that Jimmy and Roger would be targets for any hostile act. They would be in plain view while the others were not. Roger guessed something of what was passing in Jimmy's mind for he said: "There can't be any danger. Those were two of our own doughboys there." "Yes," was the answer. "I guess we can take a chance. But have your automatic ready while I show the glim. No telling what may happen."