The Duo (2011)

The drama tells the story of two men who were switched at birth. A twist of fate results in Chun Doong, who is of noble birth, living his life as a slave and later becoming a heroic outlaw, while Gwi Dong was born as a beggar but lives Chun Dong's life as a nobleman, growing up to become a police chief. They both fall in love with the same girl, Dong Nyeo.