Samuel Kepler is an unstable cop suffering from a dissociative identity disorder. His mind is a crowded place: three other individuals share it with him, competing to take control of his personality. Following an operation that ended badly, Kepler was transferred to a small police station in Calais, Northern France. He has a desk job there and has ruled out going back into the field and risking a relapse. But he has not reckoned with the situation in Calais, a very different kind of city, and the death of girl whose body is found on the site of the refugee "Jungle". So Kepler is forced to confront his worst fear: getting back out on the street and investigating. He teams up with Alice, a local cop who hates migrants even though she herself comes from an immigrant background.