Bernard has discovered that his wife, Jacqueline, is having an affair with Robert. Being a reasonable businessman, Bernard gives Robert two options to compensate for the affair: either he will sleep with Robert's wife in order to keep things even, or he will have him killed.

Needless to say, Robert chooses to let Bernard sleep with his wife. Scheming to woo her, Bernard arranges an evening meal with both couples present -- much to the frustration of their overworked and underpaid maid, Marie-Louise. However, instead of bringing his wife to the dinner, Robert pays Barbara, a call girl, to pose as his wife for the evening. Meanwhile, Jacqueline does not know that Bernard has found out about her affair and is stunned to learn that their dinner guests are in fact her lover and, supposedly, his wife. The situation then becomes even more hilarious and confusing when Robert's actual wife, Juliette, turns up for dinner.