Forensic evidence concludes that the same person killed Patrick and Pernille. As Louise and Frederik probe the link between the victims, an old gang-related double murder emerges, suggesting a potential quadruple killer.

Louise believes Robin was killed by the same murderer as the other victims, but Frederik suspects his death was a stand-alone gang murder. However, Louise convinces Frederik that a fatal car accident links the killings

With Louise's world falling apart, the case is taken over by Jacob, Frederik’s second-in-command. Jacob is determined to track down the killer, but must also contend with Louise - who soon discovers a shocking new lead.

Alongside Jacob, Louise tries to prove Gunnar’s guilt and uncover his motive. It appears that the loss of his daughter in a car accident and the driver's short sentence was the catalyst for Gunnar's murderous campaign.