With a reign of terror that spanned almost 20 years, Delroy Grant was one of the UK's worst rapists. Nicknamed "The Night Stalker," he would sneak into the homes of the elderly and assault them before disappearing into the night. He went undetected for many years due in part to mistakes made by the police, but in 2009 a restructuring of the investigative process put them hot on his trail.

Christopher Donovan, his brother Philip, and friend Richard were in high spirits walking home in the early hours one Saturday morning when they were attacked by thugs. The gang kicked and punched Christopher, knocking him to the ground, and his lifeless body was then hit by a passing car. A painstaking investigation followed to identify the three killers, using reconstructions and witnesses.