Christian Legagneur is a very popular TV Show announcer and producer. He invites the journalist Roland Wolf to spend a few days in his country house, in order to write his biography. There, Christian lives with his god daughter Catherine, who used to be the best friend of Madeleine, Roland’s missing sister. Roland discreetly investigates, finding out that Catherine suffers from a strange disease. He soon unmasks Legagneur, who tries to kill Catherine to recover her fortune. His ultimate show will be given live, as he admits his crime on TV, and mentions his contempt for his so supportive public.