The author of the Sin Eater returns with a rousing and propulsive novel based on the astonishing true story of the first female Pinkerton detective whose next assignment could end the Civil War in this "must-read" (Publishers Weekly, starred review) for Amy Stewart and Sarah Waters fans. Kate Warne is many things: the country's first female detective, a Pinkerton agent, and a Union spy. It's August 1861, and her latest assignment could end the bloody Civil War and bring the fractured United States together again. All she must do is win the trust of her captive: Confederate spy and socialite Rose Greenhow. But with Rose well aware of Kate's working-class background and belief in abolitionism, it seems an impossible task. Worse, Kate has secrets that make her vulnerable, such as her forbidden love affair with a colleague. With time running out, Kate faces not only the moral and political divides between herself and Rose but also the ones she's made in her own heart. She must decide which divides are worth crossing and how far she's willing to go to defeat the Confederacy in this spellbinding and moving new novel from Megan Campisi.