Suspicious that her lawyer husband might be having an affair, a wife decides to spy around a hotel used for those flings, only to find out that her husband has been faithful.

Victor Chandebisse, an elegant barrister in the Paris of 1900, is shocked into impotency on his ninth wedding anniversary when his wife, Gabrielle, tells him that they "now have each other forever." Gabrielle's subsequent suspicions that her husband has been philandering are confirmed when a pair of his suspenders are returned from the Hotel Coq d'Or, a notorious house of assignation. (Actually, the suspenders were left there by Pierre, Victor's libertine nephew-assistant.) In an attempt to trap her husband, Gabrielle permits her childhood friend Suzanne, the wife of an insatiable and jealous South American, Don Carlos de Castilian, to write an anonymous note to Victor asking him to meet her at the hotel. Although intrigued, Victor passes the note on to his friend Henri Tournel, a man considered quite attractive by Gabrielle. When Don Carlos sees the note and recognizes Suzanne's handwriting, he sets out after her, with Victor in pursuit in order to warn Henri. At the hotel, which features an elaborate revolving bed designed to "defeat the forces of morality," all of the concerned parties converge in a welter of mistaken identities, flying bullets, and impending adultery, made only more confusing by Poche, a porter who looks exactly like Victor. Eventually, everyone returns unharmed to the Chandebisse home, where the real identity of Victor and Poche is determined, and Suzanne is reunited with Don Carlos. Victor and Gabrielle return to the Hotel Coq d'Or to become the first wedded couple ever to use the establishment's revolving bed.