For Zaria Tourmaline, the three years without her mother and brother have been lonely ones, living with a cold and distant guardian while she completes her education. Just as she is ready to join the world of adult fairies and genies, she finds a spellbook written entirely in her mother's hand. But this treasured object is not safe from a new enemy, a fairy with more power than Zaria ever dreamed existed. Only among the humans - who must never know fairies and genies exist - can Zaria hide the spellbook; but hidden magic, it turns out, can expose a fairy in ways she never thought possible . . .