"Jumping Jupiter!" exclaimed Jerry, "what's that?"
Slim, peering ahead of the other two, ejaculated something between a shriek and a groan.
Strewn about the ground of that cave, in every conceivable position of misery and torture, were the bodies of half a dozen dead men, all Germans.
The lieutenant's hand that held the light trembled slightly as he stared at the ghastly scene before him, but he was grit and courage right through to the heart.
"This is bad business," he said, "but we are under orders and we must go through with it. We cannot move the bodies out to-night."
He stepped further into the dark hole, and the other two lads followed.
Suddenly from behind them there was a grumbling, roaring crash, pierced by a cry of warning from Joe, outside.
The three whirled around, and for a moment no one could utter a word.
The mouth of the dungeon had completely caved in!
"Trapped!" gasped Jerry, who was the first to find his voice.