Teenage Caveman is a 2002 film directed by controversial filmmaker Larry Clark. It was made as part of a series of low-budget made-for-television movies loosely inspired by b-movies that Samuel Z. Arkoff had produced for AIP.
The film is set in a post-apocalyptic future, where the vast majority of humanity has died, not due to a nuclear war, but rather due to a viral epidemic. The remaining humans have reverted to primitive tribalism.
After killing his father for sexually assaulting his girlfriend, the son of a tribal leader is banished from the tribe, along with his friends. They eventually stumble upon a solar-powered city whose only two inhabitants are genetically modified to survive the plague. They view themselves as superhuman mutants who intend to recreate humanity in their own image.