Traversons La Manche

Jack Carson plays a traveling salesman, promoting a potion called Liqua-pep on the county fair circuit. While driving through Arkansas, he meets a family that owns a dairy farm and are dedicated to physical fitness.

When Jack's character, Wendy, realizes the eldest daughter, Katy (that's how it's spelled in the credits)--played by Esther Williams--is a beauty and a tireless swimmer, he wants her to attempt the English Channel as a promotion for his snake oil. Eventually, she agrees.

Along the way, she meets a Frenchman played by Fernando Lamas (who Esther marries sixteen years later) who becomes her love interest.

Esther's films tend to be light fare, intending merely to entertain while allowing her to swim in a pool, a lagoon, or wherever the script might take her. "Dangerous When Wet" includes a few upbeat songs and the usual all-American touchstones. But it is best known for Esther's underwater swimming sequence with Tom and Jerry (Jerry danced nine years earlier with Gene Kelly).