 A wife suspects her husband of having a roving eye. Her husband suspects the same about her. His business deals mean he has to cancel their anniversary vacation every year. So this year, in order to snoop on her dearly beloved, she engages a poor cabaret singer from Far Rockaway (Doris Day) to sail alone to South America under her name, so she can stay behind and keep tabs on hubby. Meanwhile her husband is suspicious so he hires a detective (Jack Carson) to watch his "wife" on her southbound cruise. But the singer s wisecracking piano player (Oscar Levant) has been pursuing her for years and he books passage too...