A woman is found dead in the steam room of a spa. She looks 20 years younger than she is. Investigations take Niémans and Delaunay to the next village.

The body of another spa client is found. What's the connection between the village, the spa director whose clients are being killed and the legends that seem to terrify everyone?

Niémans and Delaunay explore the dark side of the human soul, along a road dotted with unexplained deaths. Their bond strengthens when Camille's son gets into a desperate situation.

Camille finds a cryptic note from the killer in her jacket. A second murder occurs while relics are stolen from a nearby town.

The body of a black woman is discovered with a hash symbol carved into her forehead. Investigations lead the detectives to a migrant camp.

Camille meets the Professor, an authority figure at the camp. When a second body is found, the mystery deepens. A demon myth is terrifying the migrant camp. His calling card is a carved hash symbol.

The butler of the Monferville estate finds a 17-year-old in a pitiful condition. The teenager claims to be Herminien, a son of the family who disappeared 6 years ago. Camille is looking for her son Léo.

Camille suspects her son Léo is pretending to be the missing boy. What a shock when the grieving mother confirms that the boy is Herminien. The case takes a new turn when a DNA test reveals no match between Camille and Léo.

A mutilated corpse is found during a forest hunting party and it seems the victim was the heir to a family fortune. As Niemans and Camille question his immediate circle, his sister is also targeted.

Niemans and Camille are put on the track of a curse that is rumoured to be placed on the sons of the Von Geyersberg family. But are the rich clan really the victims or is there a killer among them?

In a wine-growing region at harvest time, a battered corpse is discovered under rubble when a vault collapses during the renovation of a chapel, destroying a fresco. Was it an accident or foul play?

When Niemans obtains X-ray images of the damaged frescos, they provide further insight into the case, but does a missing fragment from the biblical scenes portrayed hold the key to the killer?

When two men discover the severed hand of a child, Niemans and Camille find the local police distracted by the case of a serial killer armed with a rifle. Can they find clues at a children's home?

Two more people are shot dead, in the cemetery: a married couple who took in foster children. But a quotation from an ancient tale about an ill-fated group of children on a memorial provides a clue.

Niemans witnesses the death of a monk named Brother Guillaume who utters the words 'the sword and the snake' with his dying breath and has the palm of his left hand burned to hide a mysterious tattoo

It seems the monks believe they have discovered sinister secret messages in the ancient music they've been studying. As Camille and Niemans get closer to the truth, they encounter a satanic sect.