The blandness was gone from the other's face now. The deep-set eyes were cold, the sardonic lines set. He said: "There's another reason, Doctor. I like my life; I like my wife. And I'm afraid the temptation to relieve me of both might prove too great for you." "You're being absurd," Horning snapped. "Not to mention insulting." "Am I?" His counterpart smiled thinly. "I doubt that, my friend. You see, we're one, really. Though we live on separate planes, we both feel the same drives, the same tensions, the same impulses." "You're talking nonsense!" "No nonsense, Doctor." The pistol in his counterpart's hand was very steady. "Given the proper pressure, a strong enough motive, I know that even I could kill. In your situation, I'd certainly feel justified in murdering you. So I have no intention of giving you the chance to make me your victim." "So--?" snapped Horning. "So, you're going to leave now," his coexisting self answered bluntly. "You can be thankful I'll even let you go alive." He gestured with the pistol. "Strap on your unit. And be assured I'd have no hesitancy about shooting you if I have to." Horning clenched his fists, caught up in a churning sea of fury. "So help me--!" The gun centered on his belly. "I'll give you till I count ten," his counterpart clipped tightly. Horning bit down hard. Pivoting, he hoisted the transdimensional registration unit from the floor and strapped it into position. "In case you have any foolish ideas of coming back, let me warn you that I intend to set up a force barrier around this place," the man with his face observed with grim malice. "If you try to breach it, I'll kill you on sight." Wordless, still seething, Horning switched the projector drive to reverse. The room grew shadowy about him. His counterpart faded. Horning pressed the disintegrator button. * * * * * Of a sudden, room and counterpart were gone. Once more Horning stood alone in the vastness of the shining silver plain. His head throbbed dully; he felt incredibly tired and drained. For a moment he almost considered going back to his own world ... back to Myrtle. But nightmare memories of the empty, bitter life they'd led rose up to steel him, all hatred, conflict, tension ... so different from the happiness of the other days, the days with Margaret. Margaret.... He touched her picture, still safe in his pocket. There were other worlds--an infinity of them. Somewhere, sometime, he'd find the one world he sought. Again, he turned the transdimensional registration unit's dials. Light flashed on the scanning scope's screen. Stiff-fingered, Horning focussed.