Instantly it began to recreate the world of his nightmares. The world which had obscurely dominated his life and turned him to dream-research, where he had found similar nightmares. The world where danger lay. The blue-litten world in which a mushroom growth of ugly squat buildings, like the factories and tenements and barracks of ancient times, blotched the utopian countryside, and along whose sluice-like avenues great crowds of people ceaselessly drifted, unhappy but unable to rest--among them that other, dream Thorn, who hated and envied him, deluged him with an almost unbearable sense of guilt. * * * * * For almost as long as he could remember, that dream Thorn had tainted his life--the specter at his feasts, the suppliant at his gates, the eternal accuser in the courts of inmost thought--drifting phantom-wise across his days, rising up starkly real and terrible in his nights. During the long, busy holiday of youth, when every day had been a new adventure and every thought a revelation, that dream Thorn had been painfully discovering the meaning of oppression and fear, had been security swept away and parents exiled, had attended schools in which knowledge was forbidden and all a man learned was his place. When he was discovering happiness and love, that dream Thorn had been rebelliously grieving for a young wife snatched away from him forever because of some autocratic government's arbitrary decrees. And while he was accomplishing his life's work, building new knowledge stone by stone, that dream Thorn had toiled monotonously at meaningless jobs, slunk away to brood and plot with others of his kind, been harried by a fiendishly efficient secret police, become a hater and a killer. Day by day, month by month, year by year, the dark-stranded dream life had paralleled his own. He knew the other Thorn's emotions almost better than his own, but the actual conditions and specific details of the dream Thorn's life were blurred and confused in a characteristically dreamlike fashion. It was as if he were dreaming that other Thorn's dreams--while, by some devilish exchange, that other Thorn dreamed his dreams and hated him for his good fortune. A sense of guilt toward his dream-twin was the dominant fact in Thorn's inner life. And now, pushing through the forest, he began to fancy that he could see something at the receding focus of his vision a dozen yards ahead, something that kept flickering and fading, so that he could scarcely be sure that he saw it, and that yet seemed an embodiment of all the unseen forces dragging him along--a pale, wraithlike face, horribly like his own. The sense of a destination grew stronger and more urgent. The mile wall of the Opal Cross, a pale cataract of stone glimpsed now and then through overhanging branches, still seemed to rise almost at his heels, creating the maddening illusion that he was making no progress. The wraith-face blacked out. He began to run.