Venice, 1585. When 16-year-old Laura della Scala learns that her older sister, Beatrice, has drowned, she is given no time to grieve. Instead, Laura's father removes her from the convent where he forcibly sent her years earlier and orders her to marry Beatrice's fiancé, a repulsive old merchant named Vincenzo. Panicked, Laura betrays a powerful man to earn her way into the Segreta, a shadowy society of women who deal in only one currency—secrets. The Segreta seems like the answer to Laura's prayers. The day after she joins their ranks, Vincenzo is publicly humiliated and conveniently exiled. Soon, however, Laura begins to suspect that her sister's death was not a tragic accident but a cold-blooded murder—one that might involve the Segreta and the women she has come to trust.

In a society of liars, who do you trust? It is 1585 in Venice, and three months have passed since Laura della Scala solved her sister's murder after joining the Segreta, a powerful society of women who trade protection for secrets. Now Laura is engaged to her true love, Roberto, and she has never been happier. But the night Laura is sent on her first important mission for the Segreta, Roberto is found with the body of a dead woman in his room. Halim, an irresistibly handsome Turkish prince on a diplomatic visit to the city, identifies the woman as his sister and insists that Roberto be executed for her murder, or the Ottoman Empire will attack Venice. Laura is desperate to save both her city and her fiancé. But as the evidence against Roberto builds and Laura finds herself increasingly drawn to Halim, she begins to wonder whether everything Roberto told her was a lie. What Laura discovers is a conspiracy that involves nearly everyone she knows.