All four episodes of the crime drama starring Philip Glenister and Steffan Rhodri. In 1973, three 16-year-old girls were murdered but the police were unable to connect the cases or identify the killer. Nearly 30 years later, advancements in DNA testing lead to the cases being reinvestigated. DCI Paul Bethell (Glenister) has been haunted by the crimes and by mistakes he witnessed in the original investigations and now, with the help of Phil Rees (Rhodri) and DC Geraint Bale (Gareth John Bale), he is determined to finally bring the murderer to justice.