There was a faint grin on Villanowski's homely face. "Sound waves set its mechanism in operation. I read a story when I was a youngster—Ali Baba and the Forty Thieves," he confessed. "When I built the lock I couldn't resist designing it to respond to those vibrations." The ship rocked slightly. "What's that?" "Felt like the blow-back of an atom jet," Gavin replied tersely. "I think Y's ship, the Comet, is landing." The Nova rocked again, more violently than before, and a faint rush of flaming jets penetrated to the engine room. Villanowski scuttled through the door with Gavin prodding Nadia after him. The chief darted for the control board, seized a gleaming lever, slid it cautiously along a slot. The huge spherical tube, which Gavin had observed before, began to glow gently. The yellow mist, he saw, was gathering in the outer room, but the air in their chamber remained crystal clear. "The time field," Villanowski explained, "creates a neutral area, an oasis, around the point of generation." Gavin rubbed his eyes. On the other side of the door was nothing! It was like looking out into the void beyond the farthermost limits of the stars. "Now, Murdock," Gavin heard Villanowski ask, "when do you expect the interplanetary patrol spacers to land?" Gavin wheeled around. There was an uncertain smile on Villanowski's homely features. "How did you know?" "The little death," Villanowski explained complacently. "When Miss Petrovna told me her dream, I knew...." "You are a T.I.S. agent!" Nadia interrupted in an odd voice. She put her hand on Gavin's sleeve. "You're going to turn me over to the courts?" Two white patches appeared at the corners of Gavin's mouth. "Sure. The patrol spacers are on their way. I couldn't turn them back now—" he paused—"even if I wanted to." "Give me a chance, Gavin?" He asked, "Why did you sell out to Tri-World?" The girl lifted her eyes to his. "I was proscribed. Tri-World has granted me amnesty. That was their price. My life. I wouldn't have done it, Gavin, but I was afraid." "Does that explain why you tried to double-cross Tri-World in the first place?" "I told you about that." "And what about Trev? He hid you out when you were proscribed. He got you aboard the Nova. Why did you sell him out to Cabot?" "But I didn't. I—I...." "Don't lie to me," he said and gripped her shoulders. "You'd made your dicker with Tri-World. Trev was in your way. He knew too much about you. He might even have got wind of what you were up to. So you went to Cabot and told him about Trev being a dealer in scientific secrets. You knew Cabot would kill him, thinking the Martian had sold out to X." The girl flinched. "I'm not asking you to shield me, Gavin. Turn me loose. Just let me have a fighting chance to escape. Give me a chance, Gavin." "And Cabot," Gavin continued inexorably, his pale blue eyes stony. "You delivered Cabot and the Nova over to Tri-World."