Cecilia, the daughter of a marquis, makes a startling discovery: she has been reborn into an otome game as the villainous daughter. Despite her efforts to change her fate, she faces condemnation after ending her engagement and being falsely accused by the game's heroine. Descending into a life of hardship, she encounters her first client, the formidable deputy leader of the Imperial Guards, Lucas Herbst. Overwhelmed by fear, Cecilia finds herself in the Duke of Herbst's residence the next day, marked as Lucas's betrothed with a vow etched on her lower abdomen. The unexpected turn of events leaves Cecilia questioning her new reality and the intricate web of relationships she now finds herself entangled in.