When Chicago musicians Joe (Tony Curtis) and Jerry (Jack Lemmon) accidentally witness a gangland shooting, they quickly board a southbound train to Florida, disguised as Josephine and Daphne, the two newest and homeliest - members of an all-girl jazz band. Their cover is perfect... until a lovelorn singer (Marilyn Monroe) falls for Josephine, and ancient playboy (Joe E. Brown) falls for Daphne, and a mob boss (George Raft), who refuses to fall for their hoax, wants them put on ice for good.