The six-part crime thriller, set in Edinburgh, tells the story of Detective Inspector Ray Lennox (Dougray Scott) investigating a missing schoolgirl. As the disappearance of the girl frightened the center of the city, Lennox and his colleagues tried to find out what had happened, while he struggled with his own personal demons and infighting broke out within the police force. At the same time, watching and waiting in the shadows are cruel killers ready to attack. This film is adapted from the novel of the same name by Evan Welsh, the original author of guessing the Train.