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.
^Pomerance, Murray; Gateward, Frances K. (2005). "Where the boys are: cinemas of masculinity and youth". Contemporary approaches to film and television series (Wayne State University Press). p. 98. ISBN0814331157.