Nox

During a police operation taking place in Paris' underground tunnels, young lieutenant Julie Susini disappears under the eyes of her partner, Raphaël Berger. The police search party find nothing. Julie's estranged mother, retired cop Catherine, decides to lead her own parallel investigation. Together with Raphaël, she goes deeper into subterranean Paris, a forbidden maze of rooms and passageways. There, they make a shocking discovery: corpses, cemented and stuck in the wall like Pompeii's bodies.

Catherine and Raphaël find out that a policeman was tracking Julie. Under threat, he reveals why she disappeared: with a group of colleagues she took part in a police self-administered justice killing. They shot three teenagers. Julie was going to confess, so her colleagues had to get rid of her. They gave her body to a man who disposes of corpses in the underground tunnels, the « gravedigger ». In the meantime, a second mass grave is discovered, filled with fresh bodies: there is an active killer in the underbelly of the city.

As police chief Garraud inspects the underground lab with one of Julie's colleagues, we find out that they too are involved in her disappearance. Now that the gravedigger has been discovered, Garraud embarks on a killing spree to silence every witness. Meanwhile, Catherine and Raphaël run from the police to continue their investigation. With the help of a brilliant hacker, they infiltrate « Nox », a Darknet human trafficking auction.

Nox sells people the license to do something unspeakable to another human being. Julie is among the victims put on sale. Catherine pays a fortune for her and is led by Nox administrators to the underground room where Julie is held. So, the final act of this story unfolds, a desperate fight for survival in the darkness beneath the city.