In a post-apocalyptic future mankind is lives in a prehistoric manner. After killing his father for sexually assaulting his girlfriend, the son of a tribal leader runs away with a group of his teenage friends. They are taken in by Neil and Judith who introduce them to the vices outlawed by their tribes namely sex and drugs.Neil and Judith, however, are genetically altered indestructible mutants who have their own plans for the future of the human race.

Ken Park focuses on several teenagers and their tormented home lives. Shawn seems to be the most conventional. Tate is brimming with psychotic rage; Claude is habitually harassed by his brutish father and coddled, rather uncomfortably, by his enormously pregnant mother. Peaches looks after her devoutly religious father, but yearns for freedom. They're all rather tight, or so they claim.