Once upon a time… A plague sweeps across the emerald hills of Uí Néill, leaving a young midwife's father with months to live. To save her people, Sorcha makes a deal with a dangerous Fae. She must travel across the sea, through merrow and kelpie lands, to find a forgotten king on a crumbling throne. Born king of the Seelie Fae, Eamonn fought battles unnumbered to uphold honor, duty, and freedom… until his twin brother sank a blade between his shoulders. Crystals grew from the wound, splitting open skin and bone. His people banished him to a cursed isle for his disfigurement, now king of criminals and fools. With the help of brownies, pixies, and will-o'-the-wisps, Sorcha battles to break through his crystalline shell and persuade him to take back his stolen throne. This determined beauty could come dangerously close to stealing his beastly heart.