In October 1986, nine-year-old friends Karen Hadaway and Nicola Fellows were found dead in Wild Park on the outskirts of Brighton, having been strangled and sexually assaulted. This documentary follows police and scientists using cutting-edge methods as they attempt to uncover enough new evidence for the CPS to pursue a fresh prosecution against Russell Bishop - who was acquitted of the murders in 1987 - and charts the journeys of the families of Karen and Nicola as they try to find justice for the girls.