Deep-sea fishermen, dolphin researchers, smugglers and a legendary island in the middle of the rough Atlantic. Never again did Inspector Dupin want to investigate at sea. But in his fifth case, he finds himself on a beautiful June day on the far west coast of Brittany. On the unique Île de Sein, where more rabbits than people live, the hairdresser comes by boat and once powerful witches and even the devil himself lived. Against an impressive backdrop - between the islands of Molène, Ouessant and the bay of Douarnenez - the inspector and his inspectors investigate a puzzling case that demands everything of them, including going beyond their own limits.