An astronaut exposed to cosmic rays outside of Saturn's rings returns to Earth and begins to melt away. Escaping from the hospital, he wanders around the backwoods looking for human flesh to eat.

Coy "Cannonball" Buckman and his blazing red Pontiac enter the Trans-America Grand Prix, an underground road race spanning the continent in which there are no rules, no speed limits and no heed for the law. En route, Buckman jockeys with an international ensemble of racers for a $100,000 purse. But there are none more important than Cade Redman, his direct competition for a guaranteed spot on the elite Modern Motors racing team.

In a boorish future, the government sponsors a popular, but bloody, cross-country race in which points are scored by mowing down pedestrians. Five teams, each comprised of a male and female, compete using cars equipped with deadly weapons. Frankenstein, the mysterious returning champion, has become America's hero, but this time he has a passenger from the underground resistance.