Plot synopsis from WillyFogg.com:
Written in 1941 by Frenchman Jean Anouilh (and titled Le rendez-vous de Senlis), the play concerns Georges Delachume, a young man of considerable charm and no scruples. Georges is married to a rich, hysterical wife; they live in luxury in Paris, and their worldly goods are shared by Georges' parents and his best friend Jacques, not to mention Jacques' wife Barbara -- all of whom have been in comfort for years. Then into Georges' life comes Isabelle, a quiet young girl with a kind heart and none of the sophistication to which he has been accustomed. Georges is swept off his feet by her simplicity, and succumbs to a longing for an uncomplicated life shared, of course, with Isabelle.
He spins stories for her about the parents and friends he would like to have. He asks her to dine with his family. And when she accepts, he must reproduce this fictitious background for one night, or lose Isabelle. He hires house, servants and stage parents, but his real family materializes, and Isabelle discovers the truth. Georges, after a scene with his wife in which she tries to shoot him, thinks he has lost both his present and his future. However, the hangers-on recognize defeat and retire one by one, Georges and Isabelle are left to a future of love and simplicity far away from Paris and its intrigues.