"Well, maybe I'd better be looking to see if I can find the old tunnel," said Jimmy. "We'll need to find that, anyhow, to get ourselves out, as well as Iggy. Roger, you come with me. Bob and Franz can stay with Iggy. We'll be back as soon as we can," he added. The two boys climbed over the débris, flashing their pocket torches at intervals, so as not to use up the batteries too quickly. Bob and Franz made Iggy as comfortable as possible. "Seems to me the place was over here," observed Jimmy, as he pulled aside some loose and splintered boards. Quickly Jimmy flashed the gleams of his small lamp over the cracked and broken walls of the dugout. At first he had no success, but finally he found what he was looking for. "Here it is!" he cried. "An old door! It's been closed for some time, but here it is." "Can it be opened?" asked Roger. "That remains to be seen," replied Jimmy, as he limped nearer to it, for he had been struck on the leg by a piece of timber and he was painfully lame. An examination showed that the door, though broken and jammed, was capable of being forced open. This was done by Roger and Jimmy, using pieces of planks for levers. At last the broken door swung to one side on its burst hinges, and beyond it a dark tunnel was seen. "Here's the place!" cried Jimmy. "Now if we can go along this until we reach the other bomb-proof we shall get out all right." "Yes--if we can," said Roger significantly. "Well, we've got to try, that's sure. Can't stay here very long. It may come down about our ears." "I don't know about Iggy, though," went on Jimmy. "Of course we could carry him, but it would be hard work." However, they were not compelled to do this. For when Roger and Jimmy went back to where they had left Bob and Franz looking after the wounded Polish lad, they found that Iggy could walk by leaning on the shoulder of someone. "That's good!" exclaimed Jimmy. "Now then for the tunnel! But take it easy, everybody. We may be going into a blind lead, or a place worse than this. So go slow!" And slowly and cautiously they entered the tunnel, Roger and Jimmy in the lead. One of them flashed a pocket torch at intervals, for the way was rough and treacherous. Suddenly Roger, who had got a little in advance of Jimmy, caught the latter by the arm, and, pointing ahead, in a whisper, asked: "What's that? Who are they?" Jimmy, looking to where his friend pointed, uttered a guarded exclamation. He was gazing at a strange sight. CHAPTER III ANOTHER PUZZLE "What's the matter up ahead there?" came the demand from Schnitzel, who, with Bob, was helping along the disabled Iggy. "Why don't you go on, Jimmy?" "Is the way blocked?" asked Bob. "Are we stuck again?" "Keep still back there!" fiercely whispered Sergeant Jimmy. "Don't make such a row, or they'll hear you!"