When the mutilated body of a woman is discovered in her home, DCI Bishop from the Met murder squad is called in to oversee the case. The horrific killing bears a striking resemblance to three other murders years before, but the cases were never solved. Bishop knows they need the help of Holly Wakefield, a criminal psychologist who specialises in getting inside the minds of serial killers.

The grisly murders occur every three years, but it is the stick-man drawing left at each crime scene that has the police baffled. A post-mortem also detects a cocktail of drugs that can leave a victim screaming in silence. No one would have heard their cries for help.

Holly suspects that they are a missing a vital clue that links the victims. But can she discover the link before the killer comes knocking at her door?

Narrated by Tamsin Kennard.