To Hal and Chester, after their return from No Man's Land on the night before the opening of the German advance, it seemed that they had just closed their eyes when they were awakened by a sudden loud detonation apparently in their very ears. As both lads jumped to their feet they were borne down by an avalanche of dirt and concrete. Although neither lad knew at that moment what had happened, a German bomb had burst squarely over their dugout, shattering the little place. The boys slept in improvised bunks close to each other, and in jumping to their feet, they came closer together. They lay on the floor face down as the debris continued to rain on them. For the moment neither was able to speak. At last the shower of debris ceased, and Hal made an effort to rise. He dropped down to the floor again suddenly with an exclamation. "What's the matter?" asked Chester, sitting up. "Matter is," said Hal, "that I bumped my head. Seems like the roof has fallen in." Chester now made an effort to rise. He got to his feet more cautiously, however, and so did not hurt himself. Nevertheless, the lad gave an exclamation of alarm. "Bump your head, too?" asked Hal. "No," was the reply. "What's the trouble then?" "Trouble is," said Chester, "that we seem to be buried in here." "Oh, I guess it's not as bad as that," said Hal hopefully, and, getting to his feet cautiously, he began to explore. The dugout, before the explosion, had been a small building, possibly fifteen feet wide and as many feet long. It was entirely covered by a roof of wood. This, Hal found by exploration, seemed to have come down to within five feet of the floor and to be wedged down by a heavy weight outside. "We're buried, all right," said Hal at last, "but I guess we can get out. We'll have to dig." "All right," said Chester. "Let's begin. I've got a knife here." Hal also produced a knife and the lads fell to work upon the roof at one end. After half an hour of strenuous work Hal sat down and wiped a moist brow. "Don't seem to be accomplishing much," he said. "I should say not," said Chester as he sat down beside his chum. "I'll tell you," said Hal after a pause, "I don't think we'll ever dig our way out with these tools," and he tapped his knife. "Well, what then?" asked Chester. "We can't stay here forever. We'll suffocate. In fact, the air is already getting bad." "I noticed that," Hal declared, "which is the reason that I say we can't get out by digging. We might eventually dig our way out, if given time; but the poisonous air will overcome us long before then." "We've got to do something, Hal," said Chester. "We can't perish here like rats in a trap without making an effort to save ourselves." "Right. Then I've a suggestion to offer." "Let's have it." "It's dangerous," said Hal quietly, "and may mean only a quicker death." "Anything is better than this inaction," Chester declared.