He must come to grips with that other Thorn, settle accounts with him, even the balance of pleasure and pain between them, right the wrong of their unequal lives. For in some sense he must _be_ that other Thorn, and that other Thorn must be he. And a man could not be untrue to himself. The wraithlike face receded as swiftly as he advanced. His progress through the forest became a nightmarish running of the gauntlet, through a double row of giant black trees that slashed him with their branches. The face kept always a few yards ahead. Fear came, but too late--he could not stop. The dreamy veils that had been drawn across his thoughts and memories during the first stages of his flight from the Opal Cross, were torn away. He realized that what was happening to him was the same thing that had happened to hundreds of other individuals. He realized that an alien mind was displacing his own, that another invader and potential cryptic amnesiac was gaining a foothold on Earth. The thought hit him hard that he was deserting Clawly, leaving the whole world in the lurch. But he was only a will-less thing that ran with outclutched hands. Once he crossed a bare hilltop and for a moment caught a glimpse of the lonely glowing skylons--the Blue Lorraine, the Gray Twins, the Myrtle Y--but distant beyond reach, like a farewell. He was near the end of his strength. The sense of a destination grew overpoweringly strong. Now it was something just around the next turn in the path. He plunged through a giddy stretch of darkness thick as ink--and came to a desperate halt, digging in his heels, flailing his arms. From somewhere, perhaps from deep within his own mind, came a faint echo of mocking laughter. IV. If you can look into the seeds of time, And say which grain will grow and which will not-- _Macbeth_ Like a mote in the grip of an intangible whirlwind, Clawly whipped through the gray dawn on a steady surge of subtronic power toward the upper levels of the Blue Lorraine. The brighter stars, and Mars, were winking out. Through the visor of his flying togs the rushing air sent a chill to which his blood could not quite respond. He should be home, recuperating from defeat, planning new lines of attack. He should be letting fatigue poisons drain normally from his plasma, instead of knocking them out with stimulol. He should be giving his thoughts a chance to unwind. Or he should have given way to lurking apprehensions and be making a frantic search for Thorn. But the itch of a larger worry was upon him, and until he had done a certain thing, he could not pursue personal interests, or rest.