Rich Sadie Patch is marooned on a desert island after an emergency on her cruise-ship. With her are Irish stoker Pat, prickly young Jimmy Carrol, and bald and bookish Professor Gibble. All fancy their chances.

Magazine editor Valerie Carr lives in London with her two daughters Jan, aged seventeen, and Poppet, thirteen. When Jan is invited to a party at the Savoy, she meets dashing young Tony Ward Black mad about jive, owner of a Bentley, and supposedly running through a legacy. Attracted to the daring young man, she rejects Mark, a young farmer who is in love with her. But it soon becomes apparent to everyone but Jan that neither Tony's fortune nor even his name may be his own, and her association with him will lead her into delinquency and danger.

Lancelot is King Arthur's most valued Knight of the Round Table and a paragon of courage and virtue. Things change, however, when he falls in love with Queen Guinevere.