The killer is not only murdering his victims but mutilating their bodies in such a way that’s reminiscent of the small chestnut figurines he leaves near his crime scenes. As the detectives work to interpret the complicated web of clues, they begin to connect the dots between the string of murders and the disappearance of Kristine Hartung (Celine Mortensen), the daughter of Rosa Hartung (Iben Dorner), the minister of social affairs and a powerful political figure. Authorities believe Kristine’s case is closed, but her body has never been found, and the detectives begin to suspect that she’s alive after all.
Soon, Hess and Thulin realize that the victims of the killer are all mothers who have had complaints of child abuse lodged against them at some time, but all of them retained custody of their children anyway. More specifically, all of the victims are mothers who aren’t directly abusing their children, but rather turning a blind eye to the abuse. Detectives begin to wonder if the chestnut man killer has some connection to Rosa Hartung, and if his actions are meant as retaliation against her and the department of social affairs. The small chestnut man figurines left at the crime scenes bare Kristine Hartung’s fingerprints, could this mean she’s alive after all and was kidnapped by the chestnut man?

It’s soon revealed that before going to the foster family that abused them and that they ultimately murdered, Toke and his sister were placed with Rosa Hartung’s parents who decided to adopt the twins — that is, until Rosa became jealous of her new family members and lied to her mother about Toke treating her badly. Now, Hess is certain that Toke Bering is the chestnut man and is attempting to get his revenge on both Rosa for getting him sent away, and on all bad parents out there who allow bad things to happen to children.

After receiving mysterious messages about her daughter, Rosa shows up at the farm after Genz has already revealed himself as the killer to Thulin and tied her up there. He clearly aims to torture and disfigure Rosa like he did his other victims, but detective Hess shows up just in time. Rosa and Hess are able to free themselves from the farm despite Genz setting it on fire as he tries to escape with Thulin. Hess forces Genz’s speeding vehicle off the road, causing a crash that kills Genz.
The terrifying ordeal of the chestnut man is over with Genz’s death, but authorities still don’t know where Kristine is or if she’s even alive. Finally, the detectives are able to find the home of Genz’s sister, who has been living there in isolation along with Kristine Hartung who she helped her brother kidnap over a year ago. Kristine is reunited with her parents, apparently unharmed.
Fans of the twisting series are hoping for a season two, but so far, Netflix has yet to confirm a second season.