Based on an original idea by best-selling Danish novelist Elsebeth Egholm, the series follows the inquiries of a special unit at Copenhagen's police force, consisting of detective inspector Katrina Ries Jensen and forensic psychiatrist Thomas Schaeffer. The pair specialise in serial killers that do not fit within traditional behavioural patterns.

A love triangle between Dan Sommerdahl, his wife Marianne Sommerdahl and their best friend Flemming Torp occurs as they try to solves killings in Helsingør.

Newly divorced journalist returns to her hometown to restart her life and work through her past.