Arriving in Constantinople in 1273, Anna Zarides vows to prove the innocence of her twin brother, Justinian, who has been exiled to the desert for conspiring to kill a nobleman. Disguising herself as a eunuch named Anastasius, Anna moves freely about in society, maneuvering close to the key players involved in her brother's fate, including Zoe Chrysaphes, a devious noblewoman with her own hidden agenda, and Giuliano Dandolo, a ship's captain conflicted by his growing feelings for Anastasius. As leaders in Rome and Venice plot to invade Constantinople in another Crusade to capture the Holy Land, Anna's discoveries draw her inextricably closer to the dangers of the emperor's treacherous court--where it seems that no one is exactly who he or she appears to be.