“No,” came the response, “only jarred. But this is _some_ shell hole. I’m just beginning to get my breath. Felt as if I was dropped from an aeroplane. My searchlight seems to be burned out. Drop yours down to me; I want to look around. Easy now—reach down as far as you can and then let it go. I’ll try to catch it.” By mere good fortune he did. In an instant he had switched it on, and its glare was followed by a quick gasp from Tom and an involuntary expression of surprise. “What is it?” asked Ollie, still leaning over the edge of the pit. “What is it?” Tom repeated. “I don’t know yet, but it’s not a shell hole, that’s one thing certain. There’s a long tunnel that leads away under the ground here, and it’s big enough for a man to walk through. It runs almost due north from here, so far as I can see, but the light’s not strong enough to show how far it goes.” “A tunnel!” Harper repeated, at the same time fixing the German with a severe stare. But if the prisoner understood, he gave no sign. His only expression was one of pain. “Ollie,” said Tom, who now as a sergeant could command the other two, although he had no disposition for any unkind or unjustified use of his authority, “you’d better stay there and watch Fritz, while Harper drops down here with me. We’ll trail along the secret passageway that the Germans didn’t build for nothing, and see just where it leads.” “I’ll keep an eye on him, you can bet,” Ollie answered, as Harper, by the aid of the light Tom threw upward, dropped warily into the deep entrance to the secret tunnel. In another moment Ollie was left alone with his prisoner, and Sergeant Tom and George Harper had disappeared from sight and sound, Tom in the lead, flashing the searchlight’s rays before them as they went, Harper following close behind. They found the artificial passageway to be at no point less then five feet in height, and on the dirt surface of the flooring were imprints leading them to believe that many persons had passed back and forth through there at a comparatively recent date. Its course was almost directly northward, and the lads could at all times see some distance ahead. Nevertheless they proceeded warily, not knowing what sort of a trap might be set for them. The air was heavy and damp, but gave them no great discomfort until they had proceeded for several hundred yards, and then they concluded that the tunnel, whatever its purpose, had but one outlet, and that was the one through which they had entered. “Do you realize where this is leading?” Tom asked presently, as he half turned toward Harper. “Unless my sense of direction is all off,” George responded, “directly under Thiaucourt.” “Straight as an arrow,” Tom added, “and we ought to be almost under the town by this time.” No longer could they hear the dull rumble of the guns, and their own voices echoed and re-echoed down the cavernous passageway, the only interruptions in an otherwise dead silence.