Grieving the loss of wife and mother, Aidan and Melangell visit the renowned spiritual retreat center on the British island of Lindisfarne so Aidan can share with bright eight-year-old Melangell one of the places that inspired Jenny to write her books.

There they meet up with Jenny's friend Lucy, a Methodist minister, who is teaching a course on the local Northumbrian saints. Lucy has brought Rachel, a troubled teenager, to the Holy Island in hopes that the remoteness and peace of the location will help her.

But when Rachel is found dead on the beach, everyone on the island is...