A gas is let loose upon the world that kills anyone over 25 years old.

In a small, US costal town with many Spanish speakers, a motorcycle gang arrives on holiday. Also in town to try to reconnect with his pregnant girlfriend, Karen, is businessman Paul Collier. Paul and a leader of the cyclists, J.J., knew each other years before, so when the gang comes upon the couple and, led by the menacing Bunny, beats up Paul and begins a sexual assault of Karen, J.J. tries to intervene: he suggests they hold cycle-riding contests, with the winner claiming Karen (he promises, sotto voce, to set her free if he wins). After the contests commence, Paul crawls away to look for help. He meets with a shrug from a cowardly sheriff's deputy; where can he turn?

A motorcycle gang arrives in a small town in search of a motorcycle that has been stolen by a rival gang; but, pursued by the police, one of its members is injured, an event that will cause an orgy of violence and destruction.