Government office worker Sam Winthrop Putnam (Ray Bolger) mistakenly sends an invitation to a prestigious theater festival in Paris to New York City chorus girl Ethel "Dynamite" Jackson (Doris Day). Aboard the ship that is transporting the U.S. delegation to the festival, Sam falls for Ethel, even though he is already engaged to Marcia (Eve Miller). It will take the interference of Philippe (Claude Dauphin), a French entertainer also aboard the ship, to bring Sam and Ethel together.