All 13-year-old Blair Zielinski wants is a way off the remote Scottish island her parents have dragged her to. Roscoe is home to thousands of deer, a couple of hundred people, a complete lack of cell signal, and some unusual violet-eyed creatures.
Blair is miserable, until an otherworldly woman with antlers, one of the island's darkly magical fey folk, offers her an irresistible deal: complete three tasks and Blair's wish will be granted.
As she unravels the island's secrets, Blair soon discovers that a fey bargain cannot be broken, and her wish has put everyone on Roscoe at risk. Can Blair find a way to save her family, and the place at the edge of the silver sea that she has come to call home?