In 1960, a pilot testing an experimental rocket powered aircraft accidentally flies into the future and finds himself in a sealed city whose people suspect he is a spy from outside their walls, but who want to keep him to procreate with the ruler's daughter because the majority of the inhabitants are sterile.

A small town in Texas finds itself under attack from a hungry, fifty-foot-long gila monster. No longer content to forage in the desert, the giant lizard begins chopming on motorists and train passengers before descending upon the town itself. Only Chase Winstead, a quick-thinking mechanic, can save the town from being wiped out.