It's peak season at Morzine-Avoriaz ski resort. French high mountain state police officer Constance Vivier and Swiss cop Andreas Meyer investigate the suspect death of a teenager, found freezing on a slope after an alcohol coma.

On his birthday, Meyer receives a curious gift: a wooden sculpture of a devil with a demonic and mischievous appearance. Meyer smiles, recognizing it as a typical art object from Bessans, a village in Savoie. He calls Constance, certain that she sent him the devil for his birthday. But he's in for a nasty surprise: not only did Constance not know it was his birthday, but she's also dealing with a frozen corpse found on the French side of the border, locked in an isolated chapel in the mountains. In the victim's backpack is a carved wooden devil. It's not a murder per se, but how can anyone be sure? Did the victim lock himself in by accident, or did the door close and then jam shut after a gust of wind? Having received the same devil, Meyer decides to get involved in the investigation...