When a woman haunted by a relentless presence seeks Annie Jackson's help, Annie and her brother Lewis are drawn into an investigation that reaches deep into Scotland's darkest history. Evie Cartwright first speaks to the dead as a child. When she leaves home for university, her ability takes a terrifying turn after she witnesses a brutal murder. By morning, she is haunted by a dead serial killer who refuses to leave her alone, and marked by a cut across her neck that never heals. For the next ten years, Evie is driven from place to place, searching for a way to rid herself of the voice that torments her day and night. When desperation leaves her with nowhere else to turn, she arrives at the remote Highland home of Annie Jackson, hoping she will finally find answers. As Annie and her brother Lewis begin to investigate, helped by an old friend with specialist knowledge of the occult, they are drawn into a dark and dangerous search that reaches deep into Scotland's history. And some ghosts are not content to remain in the shadows?