The concluding part charts a decades-long quest for justice, as Arlene's family and the police fight through courtrooms and appeals to uncover the truth about her disappearance. The police investigation is rigorously tested through two murder trials and a dramatic appeals process, with the process going from the High Court in Edinburgh in 2003 to the Scottish Parliament in 2025, where Arlene's sister Carol continued her determined campaign to uncover the truth about what happened