A serial killer murders a businessman's wife, then blackmails the man into procuring young girls for him to murder. The businessman hires a gang of renegade motor-cyclists to kidnap girls for him.

Mike, a biker, returns to California after serving in Vietnam. He uses his war-hero experience to organize a new, united super outlaw gang. When one member is shot by police because he killed a girl at a pot orgy, an all-out cop vs. biker war results.

A biker gang visits a monastery where they encounter black-robed monks engaged in worshipping Satan. When the monks try to persuade one of the female bikers, Helen, to become a satanic sacrifice the bikers smash up the monastery and leave. The monks have the last laugh, though, as Helen, as a result of the satanic rituals, is now possessed and at night changes into a werewolf, with dire results for the biker gang.