Lille, at Christmas time. Thirty-year-old Claire Gautier works as an assurance assessor. She leads a peaceful life with her husband Fabrice and their little daughter, Pauline… Then Claire meets Laurent Kessler, a veterinarian who comes to see her about water damage in his apartment. So begins a story of love and terror. Laurent is a seducer, or rather, an obsessive woman chaser. But, with Claire things are different. No doubt because the young woman senses a dark side to his personality that he tries to keep hidden. Women have been murdered by a man who is spreading terror through the city. Claire can’t stop herself from making a connection between Laurent and the killer. And yet, as her suspicions become even clearer, she becomes more and more attached to him. Will she be able to escape from this spiral of fear and fascination?