Police profiler Arnar is sent back home from Oslo to his native Iceland to investigate the country's first serial killer case. He teams up with the local senior cop Kata.

A police investigator named Arnar travels from Norway to assist in the investigation surrounding Iceland's first serial killer. He works with Kata, the officer in charge of the case, and together they must race against the clock to find the murderer before it's too late. While the victims initially seem unrelated, the trail leads them to an abandoned boys' home named Valhalla, where some horrifying events occurred 35 years earlier.