Lorna Brady wakes one morning to find a corpse in her house with no idea who the dead woman is. She doubts herself, because she has long suffered from extreme bouts of sleepwalking.

In an isolated village in the north west of Ireland, a murder investigation begins when Garda Barry Roche finds a body buried in the bog. In the most personal of cases, Garda Conall Ó Súilleabháin discovers it is his mother, Sabine, who has been missing for 15 years. Conall is forbidden from working on the case, but is drawn into the investigation by a determined young journalist Ciara-Kate, who is using her true-crime podcast to expose the village's deepest secrets. As they unravel the truth, they must confront a community bound by silence and its own moral codes.