In an effort to keep from romantic entanglements, dentist Dr. Julian Winston (Walter Matthau) has been pretending that he is married with children. But when he finally decides he wants to actually marry his girlfriend Toni Simmons (Goldie Hawn), he has to first ask his nurse Stephanie Dickinson (Ingrid Bergman) to pose as his first wife so that they can both convince Toni to go ahead and marry Julian.