The "my" in My Night At Maud's belongs to the protagonist played by Jean-Louis Trintignant, a Catholic engineer whose struggle with his faith is renewed when he falls instantly in love with a woman he's never met (Marie-Christine Barrault) while attending mass. A chance meeting with an amoral old friend (Antoine Vitez) the same night places him in a potentially compromising situation when he's forced to spend the night with Vitez's alluring acquaintance Maude (Françoise Fabian), a sophisticated woman who challenges Trintignant's belief through intellectual and fleshly means.