Crown Prince Sado
The drama begins with the King's early years, during which he befriends two children working in the Palace who are later expelled. King Yeongjo (Jeongjo's grandfather) seals Jeongjo's father, Crown Prince Sado, in a rice storage chest with no food or water because he fears that the crown prince is planning a coup. Jeongjo wants to save his father, and with the help of his friends Seong Song Yeon and Park Dae Su, begs King Yeongjo to forgive the Crown Prince.