Katia, a 35-year-old researcher in a documentary production company, has a chaotic way of navigating her relationship with Fred, her boyfriend. When she takes part in a new project, she finally puts her difference into words – and this revelation will turn their life upside down.

During the visit of an old potash mining the guide and the visitors discover the corpse of a woman under a hillock of potash.The gendarmerie lieutenant Sandra Bauer goes to the old mining where she meets her assistant Laurent Bourbon and the forensic team.The woman has a wound in the crane and somebody took off an index finger.Besides the dead woman is the companion of Emilie Kern , the lawyer of her ex-husband.