Human healer Mara is sold into lifelong servitude at a vampire duke's castle, where she discovers Duke Alaric has been poisoned for years and framed as a bloodthirsty monster. As Mara treats him, the two uncover a conspiracy linking his usurping uncle to the Church that burned her mother. Fighting forbidden feelings, poisoned vampires, and a planned massacre, they expose the truth, free the victims, and choose each other—while a stolen vial hints the evil is not over.