A little girl finds a cut-off ear in the middle of "Polar Park" in Mouthe. Best-selling crime novelist David Rousseau from Paris has actually come to the coldest village in France for a different reason. He wants to visit the monastery there to see an old acquaintance of his late mother. Apparently, Brother Giacomo has something to tell him. But when Rousseau arrives at the monastery, he can only attend Giacomo's funeral. Brother Auguste gives Rousseau a hint: perhaps his mother had an affair with a man in the monastery at the time of her monastic retreat. With Giacomo, perhaps? Rousseau had actually hoped for more from the visit to the site and disappointedly makes his way back when he passes the place where the cut-off ear was found. The passionate crime writer feels directly called upon to trouble the investigators with his knowledge. When the rest of the body is found to match the ear, Rousseau happens to be in the right place at the right time again. The author enters the crime scene and meets Major Louvetot. Unasked, he bombards him with speculations about an art-obsessed serial killer who is wreaking havoc in Mouthe. Is Rousseau's writer's fantasy running away with him, or is there some truth to the supposition?