Then as if by magic those red pin points, that they now knew were eyes, seemed to spring up from every direction. There were rats everywhere, an army of them, rats ahead of them and rats behind them, gathering to oust these human intruders from their domain. Singly they were contemptible opponents, but now they had the strength that came from numbers, and they knew it. And the Army Boys knew it too. For an instant panic gripped at their hearts. The next moment they had pulled themselves together. "Back to the trap door, fellows!" said Frank tensely. "Fast, but not too fast. Don't run. And don't shoot, or we may hit each other. Draw your revolvers and club them off with the butts." They retraced their steps as well as they could in the darkness. The rats knew that they were retreating, and they grew bolder. Again and again they fastened themselves on their arms and legs, and had to be beaten off with the revolver butts. All the boys were bitten many times, and it seemed to them that they would never come to the end of the passage alive. But none of their assailants reached their throats, although one had to be knocked from Billy's shoulder, and at last the nightmare journey ended when they stumbled against the steps that led to the trap door. Frantically they heaved the door up and clambered out and sank down on the ice covered ground, spent and out of breath and utterly exhausted. CHAPTER XVIII THE CRITICAL MOMENT For a time the Army Boys sat there, panting and gasping from their unwonted exertions, yet filled with a deep thankfulness that they had won through as well as they had. At length Frank gave a short laugh that had in it little trace of mirth. "Three husky doughboys of the American Army put to flight by a horde of rats!" he exclaimed. "All the same, they'd be picking the bones of those same husky doughboys if we hadn't vamoosed," defended Billy. "Gee! it seemed to me that there must have been millions of them." "I know now how that Bishop Hatto, or whoever it was, felt when the rats were after him," put in Bart. "If we'd only had some clubs with us we might have had a chance." "Well, they made us show our backs, and that's something the Huns were never able to do," said Frank. "But I guess we'd better get back to the barracks and cauterize these bites. I don't know how you fellows made out, but I'll bet they bit me in twenty places. I'm bleeding fiercely." "Same here," echoed Billy. "I feel as though I were one big wound," said Bart lugubriously. "But say, fellows, don't let on what we've been up against or the boys will guy us to death." "And to think we've been to all this trouble only to find that we'd stumbled into a sewer," said Frank disgustedly. "That's what it must have been, guessing by the smell." "Oh by the way!" exclaimed Billy, as a thought struck him. "I meant to tell you fellows, but the fight with the rats put it out of my mind. There was an electric light in one of those passages."