The brutal murder of a French citizen sees French homicide investigator Kahina Zadi go to Kiruna, Sweden - a small town in the Arctic Circle where the sun doesn't set. Together with Rutger Burlin she begins an investigation that soon takes on staggering proportions.

Kahina Zadi and Anders Harnesk are desperately looking for a connection between the bestial murder of Frenchman Pierre Carnot and the helicopter pilot Kambo. On a notice board in a shop Anders happens to see a note with Kambo’s name and the number 20 on it. A note with Carnot’s name and the number 21 is also found. Anders and Kahina realise that this is just the beginning.

It is clear that the horrific murders committed in Kiruna are part of a hit list. Three men are already dead, and when Anders studies the murder scenes more closely he finds evidence pointing towards the Sami. If this becomes public the small mining community might be torn apart by hatred and conflict. The autopsy report shows that Chief Prosecutor Burlin was poisoned with rare herbs. Shaken, Anders visits a shaman on the mountain to find out who could supply the herbs. Noaidi gives him a name.

Injured and exhausted, Kahina is held captive by the confused and intoxicated Bangkok Jori who admits that he sold the herbs that killed prosecutor Burlin. Back in Kiruna, Kahina is approached by a threatening Frenchman who demands that she keeps him informed about everything in the investigation. Kimmo and his miner colleagues all receive a video on their mobile phones that shocks them. Someone knows what they have done.

Anders receives information about another murder, and is becoming increasingly concerned about Kahina’s whereabouts. Waiting outside the police station is a young Frenchman who claims that he is Kahina’s son. Sparen considers going to the police to tell them everything he knows, but first he calls a meeting.

Anders and Kahina find unexpected and unpleasant links between the murder victims, and some of the residents of Kiruna. Kahina’s boss in Paris orders her to report her findings directly to the mysterious Frenchman. This is no longer an ordinary murder investigation, and Kahina begins to fear for her son’s life.

Eddie starts a fire in the depths of the mine, as Kahina races to stop his plan coming to fruition.