Willie Duggans, a tenderfoot from the east, arrives in the wild west and soon experiences its violence. Willie discovers the easy money in bounty killing and must choose between that violent lifestyle and the love of a beautiful saloon singer.

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.

Local beach-goers find that their beach has been taken over by a businessman training a stable of body builders.

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.

The film takes place aboard an American submarine in the Pacific during World War II. The sub's commander is ordered to stop and pick up an underwater demolition team led by Lt. Hayes, whose mission is to locate and destroy a US submarine sunken in a lagoon off Bikini Atoll before the Japanese are able to raise it and capture the advanced radar system on board.