Madrid, late in the sixteenth century. Luzia Cotado is a scullion in the household of Marius and Valentina Ordoño, scraping through her days of endless work with the help of a small, hidden talent for miracles. When her scheming mistress catches her at it and sees a chance to climb, Luzia's magic stops being a secret and becomes a currency.
Word of her gift reaches Antonio Pérez, the king's disgraced former secretary, who needs a holy champion to win back royal favour. Luzia is entered into the Torneo Secreto, a secret tournament against three rival miracle workers — a girl who sees visions, a farmer's son who conjures with a lute, and a beauty who claims to speak with the dead. To prepare her, the nobleman Víctor de Paredes lends her a tutor: Guillén Santángel, an embittered immortal familiar bound to de Paredes's service and carrying secrets of his own.
But Spain burns what it cannot explain. Every trial that raises Luzia's profile draws the Inquisition nearer to her Jewish ancestry, and the same gift that might make her fortune is the one that can put her on the pyre.