The financial crisis is raging and the number of bankruptcies and repossessions is on the rise, but Detective Inspector Sarah Lund has a newfound sense of peace in the form of a new job, a new home and the recognition of achieving 25 years of service in the Police Force.
What appears to be a random murder at a scrapyard in the Copenhagen docks begins to interfere with Lund's plans for a quieter life and draws attention towards the shipping and oil giant Zeeland, run by billionaire Robert Zeuthen, who is the third generation head of the family to run this business empire. He is already troubled by his recent divorce and internal struggles within the company.
Meanwhile Sarah Lund is disturbed by an old flame, Mathias Borch, from the National Intelligence Service (PET) who fears that the killing in the docks is the beginning of an assassination attempt upon the Prime Minister. Prime Minister Kamper is himself in the middle of a turbulent election due to the pressures of the financial crisis and is looking for backing from the commercial sector, including Zeeland. Rumours arise that Zeeland is threatening to move the company and its production aboard--a potential disaster for the local economy.
Both Lund and the investigation quickly become embroiled in the politics of the financial crisis and all too late she begins to piece together the perpetrator's plan and the sort of debt he is seeking to reclaim; a moral debt which costs lives and involves the taking of a particularly chosen hostage.
Destinies cross over all sections of Danish society as the hunt for the perpetrator intensifies towards a dark secret which eventually puts everything at stake for both the Prime Minister, Robert Zeuthen and Sarah Lund.