The hunt to catch the killer of three young women in the Port Talbot area in 1973 and the remarkable story of how - in the first case of its kind - the mystery was solved almost 30 years later using pioneering DNA evidence. Contrasting the policing methods of the 1970s with the forensic breakthroughs of the early 2000s, the series portrays a town dealing with the repercussions of an unsolved case three decades on, and asks if justice can ever truly be found.