Funny things happen when a scatterbrained young American named Mike goes to Paris to become rich and famous composing wise and wonderful aphorisms. Commercial success eludes him, yet he nevertheless enjoys an exciting lifestyle of Left Bank hijinks...until he meets and marries a strange Russian girl whose family makes its living by stealing from senile old people. As the story begins, Mike is living with his wife's family in a large apartment belonging to his wife's wealthy godmother. The family is bilking her. Furious at his ignoble domestic situation, and disappointed by the failure of his aphorisms business, Mike decides to murder the leader of the family, his wife’s diabolical aunt, in order to win the godmother's fortune for himself. He enlists the help of two friends: a highly competent but amoral Englishman and a crazy Italian-American painter. Elaborate schemes are hatched, all of which move Mike toward a new career, one less glamorous than originally envisioned but better suited to his talents.