Robert Block (Rémy Girard), a respected psychiatrist, discovers that his young wife Carole (Natacha Régnier) is cheating on him. Therefore he gets completely thrown off course. His jealousy prevents him from concentrating on his patients; until Léo Debond (Laurent Lucas), a psychotic and depressed single man, seeks help from him. Robert meets him with a mixture of compassion and secret contempt. 

When Carole wants to leave him, he cunningly exploits his patient's trust and dependence and makes him a stooge for a murderous plan to end his pain.