Após uma guerra nuclear ter destruído a maior parte da humanidade, um pequeno grupo de sobreviventes se reúne na segurança de um vale isolado. Mas seu refúgio está ameaçado por um monstro hediondo e mutante que espreita na floresta.
"Genius" accidentally invents "goo" which causes living things to rapidly grow to an enormous size. Seeing an opportunity to get rich, some delinquent teenagers steal the "goo" and, as a result of a sophomoric dare, consume it themselves and become thirty feet tall. They then take over control of the town by kidnapping the sheriff's daughter and dancing suggestively.
When Frank Michaelson, well-respected president of the board of education, is falsely accused of horseplay, he blames his 19-year-old daughter, who has grown into a desirable young woman.
