The killing of a local minister leads DCI Tom Mathias and DI Mared Rhys to a remote community in the mountains. Confronted by a family in grief and a community in shock, they must tread carefully as they investigate the life and violent death of the troubled victim. As the case continues, DS Sian Owens leads a separate investigation into the recent attack on DCI Mathias, an attack that left his home destroyed and his skull split open. DS Owens's investigation is an unwelcome distraction for DCI Mathias, and he struggles to keep his emotions in check as the two cases unfold.

Laura Dean, a curator, is discovered in a shallow grave in remote woodland. Mathias and his team must delve into the young victim's life to unearth some shocking secrets. Meanwhile, Prosser - still reeling from the death of Iwan Thomas - calls on the help of retired Chief Inspector Robert Owen.