The conclusion to this two-part true crime docudrama, featuring powerful first-hand accounts from police who cracked the case, parents who tragically lost their children, and chilling interview tapes in conversation with a serial killer.

After a van driver named Robert Black is caught in 1990 abducting a young girl in the rural village of Stow, detectives believe they have their strongest suspect to date, in a by-then eight-year investigation into the murders of small, young girls across Great Britain.

But Robert Black refuses to talk. And with a distinct lack of physical and forensic evidence, detectives face one of the biggest challenges of their careers. Can they prove that Black is responsible for the vicious murders of girls as young as five years old? If the officers are to close the net on Black, it will take every ounce of old-fashioned police work.

Many years have passed since the parents of Susan Maxwell, Caroline Hogg and Sarah Harper saw their daughters for the last time following their abduction and murders. As they prepare for a conclusion to the case - can justice ever be done? Will the tireless police work hold up in court and convince the jury? Or will Black slip through the net?

Following the turn of the millennium, police from Northern Ireland re-open the 20-year cold case of the murder of Jennifer Cardy, strongly suspecting that Robert Black is the culprit. After years spent building a circumstantial case, the final piece of the puzzle could come in the form of a confession. They decide to interview Robert Black, opening themselves up to the mind of a cold and calculated serial killer.

Finally, 30 years Jennifer's murder, Andy Cardy waits to come face to face with his daughter's killer in the conclusion to a heartrending story that spanned more than three decades.