Rick and Penny were born and raised in the 1984-ish word of Tuan. As the two youthful representatives on an expedition back to the mother planet, Earth, they find their usefulness minimal after they survive the guinea pig experiments of the trip. The object of the expedition is eventual colonization. Humanity was not supposed to survive the ""Great Disaster,"" but as the captain points out, human remnants could be ""exterminated."" Rich and Penny escape tyrannical captain and find the joys of earth enhanced by a peaceful agricultural society they nickname the ""Hombods."" But even these simple, pleasant people are threatened, not only by the Captain but by the terror of the ""Dreadfooters,"" a humanoid race resulting from one of mankind's worst pre-Disaster machinations. Although the intricate plot is handled well, it smacks of someone tinkering around with The Time Machine, which worked better and is worth waiting for.