After a storm reveals the body of Isla Edwards with a knife wound in the Scottish Borders' Scales Valley, police officer Fiona MacLeish is drawn into the investigation. With only Isla's diary as a clue and trapped with the locals at a farm due to floodwaters, Fiona navigates tight-knit community secrets to find the killer. Amidst growing tension and with her past haunting her, Fiona races against time to prevent more deaths in the isolated community.

When eight-year-old Cait Yorke disappears on a Scottish Highlands island amidst a gathering storm, police officer Fiona MacLeish is dispatched for the investigation. Encountering secretive locals and a murder with no obvious escape route for the killer, Fiona's investigation uncovers a myriad of island secrets. With the storm escalating and a murderer on the loose, Fiona must solve the case before further violence ensues.

During a snowstorm in the Scottish Highlands, police officer Fiona MacLeish and a group of hikers face a deadly situation when one of them is found murdered. With the group stranded in a shelter and everyone harboring secrets, another attack confirms the killer remains among them. Fiona races against worsening conditions and dwindling supplies to unmask the murderer and save herself and the others from a fatal outcome.