Oops, I Slept With My Fiancé’s Uncle

In this world, marriages between families are arranged to seal business deals, and a niece taken in after her parents' deaths is raised to be married off rather than loved. Catherine grew up this way in her uncle's house, treated as a debt to be repaid and mocked by her cousin at every turn. Under a different name, she runs a music production career as "Phantom," a producer whose identity no one in the family knows. Her mother left behind a piece of jewelry called the Heart of Star, and Catherine's engagement to Nicholas, a man she cannot stand, becomes the means by which she tries to get it back. A night with a man named Julian turns out to be more complicated than either of them planned. He is Nicholas's uncle. Julian works as a jewelry appraiser, but before that he was an FBI agent, and he has been quietly looking into his father's death ever since. As Catherine and Julian keep crossing paths while working their separate angles, they start comparing notes, and the trail leads to arms dealers and to someone in the family who killed his own father. The two of them end up working together, and what started as strategy on both sides turns into something neither can fully separate from the case. The investigation and the engagement collide in public, in front of the people who set all of it in motion.