MacKayla Lane was just a child when she and her sister, Alina, were given up for adoption and banished from Ireland forever. Twenty years later, Alina is dead and Mac has returned to the country that expelled them to hunt her sister's murderer. But after discovering that she descends from a bloodline both gifted and cursed, Mac is plunged into a secret history - an ancient conflict between humans and immortals who have lived concealed among us for thousands of years. What follows is a shocking chain of events with devastating consequences, and now Mac struggles to cope with grief while continuing her mission to acquire and control the Sinsar Dubh - a book of dark, forbidden magic scribed by the mythical Unseelie King, containing the power to create and destroy worlds. In an epic battle between humans and Fae, the hunter becomes the hunted when the Sinsar Dubh turns on Mac and begins mowing a deadly path through those she loves.