Paul Diallo, a history teacher, lives a quiet life with his wife and kid. During summertime, he lends his house to his son’s babysitter and her boyfriend. When they return, the Diallo family finds a closed door – locks have been changed and the new occupants maintain they are in « their home ». With no one to turn to, Paul gets closer to Mickey, a shady local man with a penchant for all things extreme and illegal. Soon the once anti-violent teacher is approaching the point of no return…

In the small bordertown of Villefranche, lost in the heart of a large forest, crime rate is six times higher than elsewhere in the area. Each new crime Major Laurène Weiss solves with the help of her unusual team makes her sink deeper and deeper into secrets of the area.