Set in the small coastal town of Le Tréport in northern France, where the bodies of murder victims are being unearthed and left for discovery. The former chief-of-police, Paul Maisonneuve, is implicated in the murders. Detectives Justin and Sandra investigate the case.
The frozen bodies of 15 men are discovered on an abandoned bus in the middle of the northern French countryside. Detective Sandra Winckler is part of the police investigation into this mysterious find, and soon enough her team discovers the one thing that linked the dead men - all 15 had at some point been involved with a woman named Catherine Keemer. But there's a twist - Catherine Keemer herself disappeared three years ago.
Sandra and the investigating team begin to figure out the killer's modus operandi, as Sandra becomes increasingly convinced that Catherine holds the key to the mystery. But can Catherine be trusted? Is she really just an innocent victim? Meanwhile, someone else steps forward claiming to know who the killer is.
When the body of a young woman is found buried under a wind turbine, police work to figure out if and how this death might be related to the other murders. Detective Sandra Winckler starts using the same dating app that Catherine Keemer had used in the run-up to her abduction, in an effort to track down the man who snatched Catherine. But is this, and the budding friendship between the two women, a step too far in becoming personally involved in the investigation?
Believing him to be the kidnapper, Catherine holds Martin Souriau captive. She is frantic to find her missing child and will go to any length to make Souriau talk. Meanwhile, Maxine wants to take Sandra off the case and put her under police protection, along with all of her exes. Sandra reailses she is falling for Antoine, but could Antoine be the man who broke into her apartment?
Antoine's car is found on the side of the road in the middle of a forest, but there is no trace of Antoine himself. Sandra is still on the run with Catherine, as the two try to figure out who Martin Souriau is covering for and extract information from him to lead them to the killer, and to Catherine's missing baby. Meanwhile, police uncover the identity of the second killer.
Sandra investigates the Mount St Michel orphanage, and discovers an old group photo of the children who once lived there. She decides to track down each of the children. Is she starting to close in on the killer?
Sandra has fallen into the clutches of the killer, who is keeping her captive and intends to subject her, and her former lovers, to the same treatment he had given his previous victims. Meanwhile, the police investigation, now headed by Justine and Max, is getting nowhere, as Audrey Solange refuses to talk. And, worried about Sandra's whereabouts, Catherine does some investigating of her own.
Will Sandra manage to get away from Geir Jansen, or will she become his next 'bride'? What has happened to Eric and Sandra's other former lovers? Will Catherine find her baby? And who is the Minotaur? What power did he exert over the children at Mt Saint Michel orphanage?