Karen is a refreshingly normal young woman with a quick mouth and clever mind. After a promotion to Police Scotland's Historic Cases Unit, she's tasked with reopening the investigation of a young woman's murder 25 years prior. It's recently become the subject of a true crime podcast, and while suspicion originally fell on the three male students who found the body, they were never charged. As she carries out her investigation, she'll soon realise the original investigation was full of problems. Those discoveries will put her in conflict with the same officers who originally worked the case.