In Venice, the millionaire benefactor Cecil Fox watches a Seventeenth Century play ‘Volpone’ and plots a practical joke to play on his three former greedy mistresses. He hires the unemployed actor William McFly to act as his butler and stage manager and sends letters telling the mistresses he is terminally ill. The prime intention of Rex is to see the reaction of the women after the reading of his will but things do not go as planned.

Nester Patou, a naive police officer, is transferred to the red light district in Paris and organizes a raid on a dodgy hotel running as a brothel – inadvertently disrupting the corrupt system of the police and the pimps union, and netting his station superior. Fired from his job, Nester goes to the local bar for a drink and befriends a pretty young lady named Irma la Douce. Upon realizing she is a prostitute, Nester invents a crazy scheme to keep her from seeing other men.