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.

A Martian teenager sent to prepare for an invasion falls in love with an Earth girl.

Anthropology Professor Robert Orwell Sutwell and his secretary Marianne are studying the sex habits of teenagers. The surfing teens led by Frankie and Dee Dee don't have much sex but they sing, battle the motorcycle rats and mice led by Eric Von Zipper and dance to Dick Dale and the Del Tones.