Lee Yool falls off a cliff and nearly dies in an attempted assassination. He loses his memory, and wanders for 100 days under a new name and personality. During this period, he meets Hong Sim, head of the first detective agency in Joseon.
i Yul, Crown Prince of Joseon, is a perfectionist who disregards most royal palace nobles. His cold and demanding demeanor masks deeply rooted loneliness. He comes to pass a law stating that Korean citizens of marriageable age must wed before the age of 28.
Hong Sim is a strong, intelligent woman who supports herself and her father. After an attempt on his life, Crown Prince Yi Yul is severely injured and finds himself under the care of the Hong household. He’s experiencing temporary amnesia, and now unaware of his identity, he is free to wander at will as a commoner.
Due to the law, he himself passed, Hong Sim, now the oldest unmarried woman in her village, must marry or face punishment from officials. Yi Yul proposes to Hong Sim that they ought to marry.
Can their budding romance withstand Yi Yul’s eventual recovery with his memory fully intact?