The Duo is a 2011 South Korean historical drama series, starring Chun Jung-myung, Lee Sang-yoon, Han Ji-hye and Seo Hyun-jin. It aired on MBC from February 7 to May 24, 2011 on Mondays and Tuesdays at 21:55 for 32 episodes. It examines how class determines fate during the Joseon era through two men who swap lives. Switched at birth, Chun-doong and Gwi-dong grow up living each other's lives. Nobleman's son Chun-doong endures great hardships in the lowest caste of society, and becomes a vigilante who steals from the rich. Beggar's son Gwi-dong grows up in a wealthy noble family, and becomes a police chief. Living on opposite sides of the law, their paths cross again when they both fall for the same woman; played by Chun, Lee and Han respectively.