For two years, Oriana Paredes has been a spy among the social elite of the Golden City, reporting back to her people, the sereia, sea folk banned from the city's shores ...

When her employer and only confidante decides to elope, Oriana agrees to accompany her to Paris. But before they can depart, the two women are abducted and left to drown. Trapped beneath the waves, Oriana's heritage allows her to survive while she is forced to watch her only friend die. Vowing vengeance, Oriana crosses paths with Duilio Ferreira-a police consultant who has been investigating the disappearance of a string of servants from the city's wealthiest homes. Duilio also has a secret: He is a seer and his gifts have led him to Oriana.

Bound by their secrets, not trusting each other completely yet having no choice but to work together, Oriana and Duilio must expose a twisted plot of magic so dark that it could cause the very fabric of history to come undone ...