Sixteen-year-old Deirdre Monaghan is a painfully shy but prodigiously gifted musician. She's about to find out she's also a cloverhand—one who can see faeries. When a mysterious boy enters her ordinary suburban life, seemingly out of nowhere, Deirdre finds herself infatuated. Trouble is, the enigmatic and conflicted Luke turns out to be a gallowglass—a soulless faerie assassin—and Deirdre is meant to be his next mark. Deirdre has to decide if Luke's feelings towards her are real, or only a way to lure her deeper into the world of Faerie