The story takes place in four different eras. A hundred years after the time of Nathan, the world has been destroyed by a war between humans and Technodroids, half organic and half machine beings. Close to defeat, the technodroids send two agents in the past (at the time of Nathan) to change the course of future events. But, in the complex temporal game, also an enigmatic character who comes from a future far more remote than that of the technodroids, is determined to play his part.