"That's been our big problem all along," he said seriously. "We have to keep the Nipe from knowing he's being watched. In the tunnels themselves, we've only used equipment that was already there, adding only what we absolutely had to--small things. A few strands of wire, a tiny relay, things that can be hidden in out-of-the-way places and can be made to look as though they were a part of the original old equipment. After all, he has his own alarm system in that maze of tunnels, and we have deliberately kept away from his detecting devices. He knows about the rats and ignores them. They're part of the environment. But we don't dare use anything that would tip him off to our knowledge of his whereabouts. One slip like that, and hundreds of human beings will have died in vain." "And if he stays down there too long," Stanton said levelly, "millions more may die." The colonel's face was grim as he looked directly into Stanton's eyes. "That's why you have to know your job down to the most minute detail when the time comes to act. The whole success of the plan will depend on you and you alone." Stanton's eyes didn't avoid the colonel's. _That's not true_, he thought, _I'll be only one man on a team. And you know that, Colonel Mannheim. But you'd like to shove all the responsibility off onto someone else--someone stronger. You've finally met someone that you consider your superior in that way, and you want to unload. I wish I felt as confident as you do ... but I don't._ Aloud, he said: "Sure. Nothing to it. All I have to do is take into account everything that's known about the Nipe and make allowances for everything that's not known." Then he smiled. "Not," he added, "that I can think of any other way to go about it." _THIRD INTERLUDE_ Mrs. Frobisher touched the control button that depolarized the window in the breakfast room, letting the morning sun stream in through the now transparent sheet of glass. Her attention was caught by something across the street, and she said, in a low voice, "Larry, come here." Larry Frobisher looked up from his morning coffee. "What is it, hon?" "The Stanton boys. Come look." Frobisher sighed. "Who are the Stanton boys, and why should I come look?" But he got up and came over to the window. "See--over there on the walkway toward the play area," his wife said. "I see a boy pushing a wheeled contraption and three girls playing with a skip rope," Frobisher said. "Or do you mean that the Stanford boys are dressed up as girls?" "_Stanton_," she corrected him. "They just moved into the apartment on the first floor." "Who? The three girls?" "No, silly! The two Stanton boys and their mother. One of them is in that 'wheeled contraption'. It's called a therapeutic chair." "Oh? So the poor kid's been hurt. What's so interesting about that, aside from morbid curiosity?" The boy pushing the chair went around a bend in the walkway, out of sight, and Frobisher went back to his coffee while his wife spoke.