When Chicago musicians Joe and Jerry accidentally witness a gangland shootout, they promptly rush off on a train to Florida pretending to be women. Now they are Josephine and Daphne, the new and pretty instrumentalists of an all-female jazz band.
For the time being, their disguise works. But soon the amorous soloist falls in love with Josephine "disguised" as a man, an elderly millionaire hits on Daphne, and the mafia boss, having solved the mystery of the masquerade, decides to urgently deal with the witnesses.