After a stormy household scene with her lover, the playwright and actor Michel Desnoyer, the beautiful Ecaterina decides to break up and leaves the premises. Shortly after, Michel receives a visit from Françoise and her husband Fernand, returning from a long stay in the United States. As the director of the theater asks him for a new play, Michel thinks of staging the story of his affair with the fiery young woman. To play his former mistress, he hires Françoise, who has always dreamed of getting on the stage, as well as her titular servant, Maria, to play his maid. The decor of the room will be an exact reproduction of the writer's office. The evening of the premiere, Michel receives death threats. Ecaterina sent them to him and is in the room. Arguing that a playwright does not have the right to tell everyone his affairs of the heart, she continues to question him during the performance and causes a scandal. She ends up calming down and a dialogue then begins between Michel on stage and Ecaterina, a simple spectator. The next day, all the newspapers echo the unusual incident of the day before, offering unexpected publicity. So much so that the director of the theater asks Desnoyer to include Ecaterina's intervention in his play. That same morning, Michel receives Françoise in turn at his home, followed shortly by Fernand, then Ecaterina. Which accuses Françoise of having become Michel's mistress, and shares her suspicions with Fernand. But the young woman, jealous, could not know that Michel and Françoise are brother and sister. Michel and she reconcile and decide to get married. The play which tells of their romance will continue its triumphant success.