As the Icelandic prime minister’s bipolar disorder worsens, his behavior threatens to endanger the stability of his government and the private lives of his aides and political allies. Some on the prime minister’s team take pains to conceal his illness while others seize the opportunity to take advantage of it.

When a third victim is found stabbed to death, police officers Kata and Arnar realize they're dealing with Iceland's first serial killer. As they start connecting dots, the trail leads them to a mysterious and abandoned boys' home named Valhalla, where a series of horrendous crimes occurred 35 years earlier. As the past catches up with the present, more lives are in danger.