Ruth Slater (Suranne Jones off Corrie) has been in prison for 15 years after being found guilty of the murder of two policemen. Today she is being released. In her new flat, she explains to the probation officer that she has a younger sister, Katie, whom she virtually brought up and loves deeply. She was taken into care when Ruth was arrested and despite frequent attempts, she's heard nothing from her for the 15 years she was in prison. Will she be able to track down the sister who means so much to her? However, before that, she faces the daunting prospect of rebuilding her life. While she is busy finding work, learning to use cash machines and working out modern train timetables, the sons of one of her victims, outraged at her release, have vengeance in mind.