The teenage girls, Mari and Phyllis, are traveling to the city for a concert when they meet a boy, Junior, who offers to show them a shortcut. He takes them to his friend's house where they meet Krug, Sadie, and Weasel. The group is high on drugs and plan to rob the girls, but their plan goes awry when Mari and Phyllis try to escape.
Krug and his gang catch up with the girls and brutally rape and murder them. They later seek refuge at a nearby house, not knowing it belongs to Mari's parents. When they realize they are in the same house as their daughter's killers, Mari's parents, John and Emma, plan a revenge plot.
The revenge is brutal, with John and Emma torturing and killing each of the murderers in their own way. They become as savage as their daughter's killers, but with a sense of justification and moral superiority. The movie poses the question of whether vigilante justice is ever justified, and whether violence can only be met with more violence.