Two musicians (Tony Curtis and Jack Lemmon) witness a mob hit and struggle to find a way out of the city before they are found by the gangsters. Their only opportunity is to join an all-girl band as they leave on a tour. To make their getaway, they must first disguise themselves as women, then keep their identities secret and deal with the problems this brings - such as an attractive bandmate (Marilyn Monroe), and a rich and very determined suitor (Joe E. Brown).