A desperate father, Don Vicente de la Cruz, hires Alatriste to rescue his daughter from a convent where a powerful priest is said to be using the girl as his personal concubine. And he can't complain, because the priest has threatened to reveal the man's family to be "not of pure blood" - of Jewish descent - which will all but destroy the family name." Alatriste agrees to help, and several nights later, under the cloak of darkness, a rescue is attempted - but things go very badly, and Alatriste soon discovers that he has become entangled in a religious and political conspiracy that leads all the way to the highest levels of the Inquisition.