The heroine assumes another person's identity and enters the Marquis's residence. Relying on her intelligence and resourcefulness, she establishes herself in the complex household. By chance, she strikes a partnership with the true heir apparent. Together, they unravel the many mysteries surrounding the past, uncover long-buried secrets, and protect innocent people around them. As they work together to fulfill their duties and uphold justice, they gradually come to understand and trust each other. After overcoming numerous twists and turns, they find genuine love in each other and embark on a peaceful, happy new life together.