Fairies have always existed in secret, without a kingdom of their own, living side-by-side with humankind. But when one of his own children is murdered, King Oberon asks his surviving daughters - newly minted NYPD detective Charli and wingless black sheep Lucy - to find her killer amidst the citizenry of New York. As Charli and Lucy delve deeper into the mystery, they begin to discover the extraordinary measures their father has taken - some clever, some desperate - to keep an entire people hidden in an increasingly treacherous world. For Charlie and Lucy, unmasking their sister's executioner will mean confronting their own blood-drenched legacy.