Seraphina inherits her mother’s scenting gift, able to detect pheromones and bloodline truth. Betrothed to Second Prince Darian, she discovers he and her sister Liana share the same pheromones. Using the wedding-oath blanket, moon-mark incense lamp, and truth incense, she lays a trap and exposes their blood-red moon marks of betrayal at the wedding-contract ceremony. The two deny it, but Eldest Prince Cassian arrives with their letters and exposes the affair. Seraphina throws the court into uproar, revealing the queen’s hypocrisy, the royal uncle’s incest, and her cousin’s affair. She annuls the betrothal and chooses to marry Cassian. Just as their contract is sealed, Cassian collapses, vomiting black blood. While treating him, Seraphina discovers her mother was murdered by her own father, stepmother, and the royal family. In the end, she drives all the villains to their deaths, places the crown prince on the throne, and rises to the pinnacle of power.
