David Threlfall takes the role of David Baker who between 1983 and 1987 headed up the investigation into the brutal murders of two Leicestershire schoolgirls, Lynda Mann and Dawn Ashworth.

With plenty of publicity, the local teenager is released and the world is introduced to DNA fingerprinting for the first time. In the villages of Narborough and Enderby there is a complete sense of fear that a murderer is living amongst them.