Arriving in the English countryside to live with her mother and new stepfather, Jenny has no interest in her surroundings until she meets Tamsin. Since her death over 300 years ago, Tamsin has haunted the lonely estate without rest, trapped by a hidden trauma she can't remember, and a powerful evil even the spirits of night cannot name. To help her, Jenny must delve deeper into the dark world than any human has in hundreds of years, and face danger that will change her life forever.