On the Canal du Midi, a vacationing family spots a woman in the water. It is Sandrine Richomme, wife of Parisian judge Etienne Richomme who are staying on their canal boat with their young son Timothee while visiting his mother. Etienne and Timothee are at Grandmother Madeleine's (clearly a grande dame). Sandrine had been having an affair andh an argument had been heard by two young women, so local investigator Capt. Maxime Fabre has Etienne in his sites. But Comm. Izia Moreno has been sent from Paris to lead the case; she's unconvinced...