The chair of the Malmo city council is found dead right on the Danish-Swedish border on the Øresund bridge between Copenhagen and Malmo - the corpse cut in half at the waistline. Detective Saga Norén of Malmo CID is applied to the case and soon learns that the lower half of the corpse belongs to a yet unknown Danish woman. She is forced to team up with her Danish colleague Martin Rohde, who is slightly irritated by her unusual manners. At the same time, Göran Söringer is brought to Copenhagen's Rigshospitalet to receive a heart transplant.

The bomb in Daniel Ferbé's car did not go off. Instead, the car's CD player put out a disc that contains a message from the murderer, which is also published on a website. He deplores five grievances of society, the first of which shall be highlighted by the murders. Norén traces back the website of the murderer to a server of the Danish CID and Rohde reopens the case of the second victim, a Danish prostitute who disappeared more than a year ago, and obtains her diary. Eventually Charlotte Söringer manages to get her beloved husband his heart transplant.

To draw attention to the increased number of people falling through the cracks of society, the killer kidnaps a homeless man and demands a large ransom from four landlords for his survival. So what is the price of a human being after all?

Knowing the killer has carefully planned his crimes, Saga and Martin wonder whether they can catch him off guard by doing something he doesn't expect.

The murderer has groomed a number of schizophrenics to commit carefully synchronized violent crimes on the same day in Malmo and Copenhagen.

A rogue policeman is killed by someone in uniform. The detectives believe that the killer for whom they are searching was the killer. They also now suspect that the killer may indeed be one of them - that he is actually is a cop.

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.

As the investigation moves forward a new group of four, animal head wearing, eco-terrorists post a video online. Saga is having some relationship "issues".

A sunken boat containing skeletal remains is found, that appears to be related to the eco-terrorist case. Martin's son is taken into hospital in a serious condition.

A chemical plant is attacked which threatens to contaminate a water source. Saga realises living with a partner is harder than she thought. Martin looks into Saga's past.

Martin visits Jens in prison and seems to be getting to him. As they re-interview witnesses Saga suspects a statement has been tampered with. Laura regains consciousness and remembers what her assailant looks like.

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.

Saga and Henrik keep searching for a link between the murder victims. Lillian is reprimanded by her superiors. Dan finds out where his ex-wife and son are and causes trouble. The relationship between Saga and Henrik is tested to the limit and may have hit its breaking point.

Henrik believes he found the connection between all victims and an unexpected finding ends up on the investigation board. At the same time, the crack between him and Saga is greater than ever.

The inquiry into Tommy continues and Solveig still refuses to cooperate. She talks neither with Saga nor Jonas. The question is how long they can keep her in holding if they do not obtain any evidence. Lillian is still under pressure from the management to find the culprit, and now it seems that there is a leak in the department. In the meantime Saga makes a breakthrough in the search for Henrik's family.

Henrik and Astrid are trying to get used to being father and daughter again. Meanwhile Saga gets a breakthrough and the murderer is revealed and arrested under dramatic circumstances. The murderer even confesses to the six killings/revenges. But Saga discovers something which doesn't fit. She goes back to the prison in Sweden and talks to the girl who almost killed her, and here she gets a terrible suspicion: there is another killer - and there is still one person left to be a victim!