On a winding road in the Pyrenees, a car accident leads to something miraculous: the reappearance of Anna, a teenager who disappeared 5 years ago. Detective Alix Stern and Commissioner Balthus are sent into a race against time, along with Victor Ferrer, the head of the local gendarmerie. They must search for clues about the disappearance of Lucie, a young girl who was abducted at the same time as Anna and has not returned.