Final episode in this emotional four-part drama tonight which is based on a true story of the devastating impact of a child's murder amid a wave of gang violence in Liverpool. Tonight's finale sees Mercer and his associates tried for their roles in the killing of 11-year-old Rhys Jones, but the verdict fails to bring closure for the boy's parents Melanie and Steve as the fractures in their relationship come to a head. Meanwhile, an unexpected setback leaves Det Supt Dave Kelly with a tough decision to make.