It is 1952, and a young man named Bob Wilson has locked himself into his room to try to finish his thesis on metaphysics when a stranger appears out of nowhere in his room. A great dark disk, suspended in midair, hangs behind the stranger. The intruder tries to convince Bob to step through the disk, which he refers to as a Time Gate. As the two men talk, a third man steps out of the Gate. This man urges Bob not to travel through the disk. The three men get into a fist fight, and in the tussle, Bob is shoved through the Time Gate. Bob wakes up to find a middle-aged man bending over him. The man calls himself Diktor and tells Bob that they are in the Hall of the Gate in the High Palace of Norkaal, and that Bob has jumped forward in time by thirty thousand years. Diktor explains that creatures called the High Ones appeared on Earth and ruled for more than twenty thousand years before completely obliterating life on Earth as Bob would have known it. Diktor explains that he needs Bob's help in an important mission: he wants Bob to travel back through the Time Gate and convince the man on the other side to come through. Bob proceeds to travel back and forth between one side of the Time Gate and the other, and in these comings and goings, he realizes that the two men who had appeared in his room were both, in fact, later versions of himself — versions he inhabits as he travels back and forth through the Time Gate. He is unsure whether or not to trust Diktor, but he acquires objects which Diktor told him would be useful from his twentieth-century world — books on government and music records. He jumps through the Time Gate a final time and arrives in the future world as it was ten years before he met Diktor. He finds the civilization of this world upsetting and rudimentary, and introduces the inhabitants to the music of his time. He uses the books he's brought with him to rule this new version of humanity. The inhabitants of this world call him 'Diktor' — their word for chief. Bob realizes eventually that the Diktor he met long ago on the other side of the Time Gate was yet another version of himself. He prepares himself for the arrival of his past selves, who will soon arrive through the Gate and need his guidance to reach what he now knows to be his destiny.