A millionaire sets out to prove his theory that his pet chimpanzee is as intelligent as the teenagers who hang out on the local beach, where he is intending to build a retirement home.

In the fourth of the highly successful Frankie and Annette beach party movies, a motorcycle gang led by Eric Von Zipper kidnaps singing star Sugar Kane managed by Bullets, who hires sky-diving surfers Steve and Bonnie from Big Drop for a publicity stunt. With the usual gang of kids and a mermaid named Lorelei.