Genevieve, a peasant girl hunted for her father's debts, flees north to the Bloody Duke's keep after a stranger named Silas offers her one chance to survive. Alaric, the Blood Duke, freezes when he sees her face, which belongs to Eleanor, his executed betrothed. When royal assassins attack, he kisses her publicly and seals a betrothal. The contract is a cage, yet Genevieve uncovers his shadow network, a murdered exile's letter, and a conspiracy. Cedric claims Alaric signed the treaty that killed Eleanor. Isolde, the poor widow, is really the Crown's spymaster and blackmails her. Genevieve learns Alaric saved her from a fire years ago and has searched for her ever since. She retrieves the decree that clears his name. In the final battle, Alaric kills Isolde, and they survive the collapsing keep. The Crown pardons him. In the flower fields, he takes her hand, and Genevieve finally becomes his bride.
