A bus-load of children is kidnapped and are threatened to be killed. The police believe that the kidnapper is the killer, and the hunt continues.

Because the detectives suspect that a policeman is involved, a profile of the killer is developed and several police fit the profile and a search among them begins. The hunt continues and a particular suspect is found.

Things are brought closer to home when the criminal's mask is removed.

The crime spree is resolved. However, many loose threads remain.

A tanker is heading towards the bridge. When it is boarded by the coastguard the crew are discovered to be missing. The only people on board are five youths, drugged and chained. Saga and Martin are assigned to investigate the case.

Four individuals wearing animal masks post a video online claiming responsibility for the tanker Saga and Martin are investigating. Deaths are reported of people eating poisoned food. Are the cases connected?

Saga and Martin continue their hunt for the eco-terrorists, who have realised the police are on their trail.

The hunt is on for the leader of the eco-terrorists, with Saga and Martin hoping to stop any further attacks from happening.

Saga and Martin have a sketch of the suspect, but can they get to them in time to avert 'The Graduation'. Their friendship is placed under strain by Martins inquiry into Saga's past.

It becomes apparent that the case isn't over and Saga and Martin race to prevent another terrorist attack. Saga faces a decision that may destroy her friendship with Martin.

A new murder is commited involving a gruesome display of a family sitting at the table. Detective Saga Norén is tasked with the investigation together with a new Danish detective after the incarceration of Martin Rohde.

With the detectives now working on two so-called 'clown murders', a prime suspect is the traumatised son of the first victim, who is on the run. The usually phlegmatic Saga is distracted from the investigation by the unwelcome appearance of her mother, who insists on showing her a medical file, hoping to find a resolution to their estrangement.

Saga and her new partner Henrik follow leads in finding their kidnapped boss Hans. In the meantime personal developments in Saga's life influence her work as a police officer.

Saga and her new partner Henrik grow closer together while new discoveries shed light on how the murder cases are linked together.

Saga and Henrik interview the estranged sister of the latest victim, who mentions that he had been cautioned after complaints from some of his pupils. Whilst nursing the hospitalised Hans, Lillian discovers a wound inside his cheek and Saga immediately orders the re-examination of previous victims. Claus attends the gallery opening of works from Freddie Holst's private collection and is alarmed when Anneka arrives and demands admittance.

A sceptical Henrik and Saga are initially unimpressed when a young art curator suggests a connection between the murders of Helle Anker and Lars-Ove Abrahamsson and the brutal attack on Hans, but his theory leads them to interview Freddie Holst, a successful businessman with a substantial art collection. The detectives are called to yet another victim whose mutilation seems to be the work of their serial killer.

Burglars make the gruesome discovery of two new victims, which Henrik recognises reflect the title of another of Freddie Holst's artworks called Cancel Christmas. The victims were foster carers and, whilst the team await a list of their charges, Saga and Henrik receive a breakthrough lead from John's new girlfriend Tina, who has been staking out the Holst house.

As the Internal Affairs investigation continues over the death of Saga's mother, the pressure on her becomes intense. Saga, Henrik and John receive new leads when it becomes clear a potential suspect in the mysterious serial killings is actually a victim.

A captive Jeanette's whereabouts are located by Freddie using a tracking device and, with all resources being utilised to investigate the kidnapping, Saga is brought back from suspension to help Henrik follow a tip on who is behind the abduction.

Rasmus has discovered Freddie's abandoned helicopter in a disused concrete factory and is told to wait for back-up.

The head of the Danish migration agency is murdered brutally, and the murder is linked to a controversial expulsion case. Investigator Henrik Sabroe needs help from his colleague and friend Saga Norén, but she is in prison for the murder of her mother.

Henrik's two main clues in the investigation are the left-wing radical group Red October and the refugee Taariq, who has gone underground. On a personal level he tries to realize that he will never figure out what happened to his missing daughters, but then someone begins to show interest in the mystery.

Henrik and Saga suspect that Taariq and the missing expert on left-wing radicals are hiding something, and collaborate to reveal them. They disagree on how to handle the homeless girls who still refuse to give up their identity.

Taariq recognizes a car related to the case. He wants to push the owner for money, but is himself accused of robbery. Saga fears that will be more murders and Henrik's efforts for the homeless girls end up in disappointment.