Emma and Charles have lived together for ten years and have an eight-year-old son, Romain. They are reporters and live in Paris. Emma is notified by the laboratory that everything about her pregnancy test is positive, including the fact that she is HIV-positive. Her world caves in. There must be some mistake. But no, the laboratory is positive. She's got AIDS. When the news falls, she is all alone : Charles is travelling; Rozenberg, Emma's best friend, has gone to the country for the holidays... Emma is mystified. She's never run round Charles; she's never taken drugs and never received a transfusion. It has to come from Charles, then. Emma opens an investigation on the man she shares her life with. She digs into his past, telephones former girlfriends, questions Gégé, Charles' photographer pal... She digs and digs until she discovers the big lie...