Nox season 1

During a police operation in the underground Paris, the young lieutenant Julie Susini disappears. A Search is organized. Julie's mother, Catherine, a retired cop with a difficult relationship, decides to conduct her own investigation. The help comes from the daughter teammate Raphael Berger.

The police investigate a mass grave discovered by Catherine and Raphael. Divisional Commissioner Garraud calls the Quarry and Underground Intervention Brigade for help to this matter. Missing clues, Catherine seeks a track in the past of Julie and wonders what could push her daughter to resign.

Catherine and Raphael discovered that Julie was followed. A second mass grave is unearthed. Unlike the first, this one contains recent corpses. It's now obvious that a killer is raging in the Paris underground. Raphael is summoned to the IGPN.

Catherine found the box containing a freezer used to transfer the bodies. Raphael and Catherine are looking for a way to get in touch with the Gravedigger. For that they need a corpse. Catherine seeks the help of her ex-Jean-François, a doctor at the hospital.

During their inspection of the underground laboratory, Garraud and one of his colleagues discovered the identity of the Gravedigger who is in the hands of Catherine and Raphael. The individual reveals to them that he sometimes gives bodies to a certain Nox. IGPN is continuing its investigation about Julie.

Helped by a brilliant hacker, Catherine have managed to connect to the site of Nox on the Darknet. It is for her the last act of her quest to find her daughter. A desperate struggle in the darkness of the bowels of Paris.