Commissioner Larosière, a brilliant criminologist, and a young novice inspector, Emile Lampion, are in charge of the investigation. Under the fire of questions from Larosière, each other's alibis fall one by one and the police arrive at the conclusion that all could have killed Simon Le Tescou. While Edith and Victor fall back into each other's arms as in their youth, Louise tells Antonin, her lover, that she is carrying her child. He is overjoyed but Madeleine, who overheard their conversation, does not hear it that way.
