In the Joseon era, a tragic twist of fate forces a crown princess to conceal her true identity after her twin brother's death, raising her as the male heir to the throne. Years later, she rules as the cold and distant King Lee Hwi, a role she never wanted but must uphold to protect her secret and the kingdom. Her carefully constructed world begins to unravel when she reunites with her first love, Jung Ji-woon, a brilliant and compassionate royal instructor who is unaware of her true gender. As their forbidden connection deepens, the king must navigate the treacherous politics of the court, the threat of exposure, and her own yearning for a life she can never have. This poignant historical romance, starring Park Eun-bin and Rowoon, masterfully blends palace intrigue, heart-wrenching emotion, and the timeless struggle between duty and desire, creating a captivating tale of identity, sacrifice, and love against all odds.