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 cowboy rides into a small town that is ruled with an iron fist by a corrupt sheriff. He becomes involved with a pretty young town girl and some residents who are trying to oust the sheriff, resulting in a robbery, a murder and his being pursued by a vengeful posse.

Giants Mollusks are released from the earth by an earthquake and start killing people.

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.