1939. Simon Le Tescou, a cruel and tyrannical man, decides to bring his whole family together to celebrate his 70th birthday. His children are Edward, Antonin and Victor. There is also Inès, his granddaughter from Spain, who nobody knew existed. A friend of the family is Eloi, a young African doctor whose research is funded by Simon. The night before his birthday, however, he does not want to eat with them. Then he is brutally murdered. Inspector Larosiere soon discovers that there are also many other corpses in the family's closet.