Frankie and Nanette hit the beach seeking hot summer kicks in the surf! Their scavenger hunt attracts the paranoid attentions of the Wellington Cosmetic Company, run by Big Daddy Wellington (Brian Donlevy) and voluptuous daughter Junior (Jayne Mansfield). At war with Camille Salamander's (Phyllis Diller) rival company, Big Daddy dispatches his top corporate spies - portly twins Irving and Herman (Jack E. Leonard in two humungous roles) to snoop on the kids and stymie the competition.
Filmed in Florida and loaded with the surf-rock of The Wild Ones, The Fat Spy is a satirical musical comedy which digs at the hypocrisy of materialism while ogling voluptuous bikini-clad teens. Brimming with sexy non-sequiturs and featuring Jayne Mansfield in one of her last roles, The Fat Spy delivers plenty of silly shenanigans and Mod beach party hilarity.