A chubby forty-ish florist is dumped for a gorgeous young woman. She decides to lose weight and to ruin her rival's life in order to win her handsome lover back.

Having first lost his wife then his job as a tweed tailor, Alex Ponttin has devised a novel way to keep himself in touch with society. He admits himself into people's homes, by pretending to be a relative or an official, and persuading his victims to give him a night's free board: He finds at first a lunch at the horrible couple Dumont, where a thief follows him for a robbery. Alex spent an evening in front of TV at Marie, mother of seven children. He runs from Marie to find an evening and a new bed at the home of charming but shy lesbian Caroline and her funny lover Gloria. To save her inheritance, Caroline - accused for her homosexuality by her horrible sister Catherine - tells her aunt Amélie, that Gloria is her secretary and Alex her lover. So Alex has to present himself nude in Caroline's bed. He saves Carolines inheritance. The police officers investigating the case are so terminally stupid that Alex has little chance of being arrested.

Alex Berthier would love to be a famous songwriter. Meanwhile, he has to cope with unemployment, a witty 12 years old son and a rich and cute heiress who tries to help Alex as much as he tries to escape her: she brings nothing but trouble ! Fortunately, luck will strike again.