Filmed at MBC Dramia in Gyeonggi Province,[1] the series examines how class determines fate during the Joseon era through two men who swap lives.

Nobleman's son Chun-doong endures great hardships in the lowest caste of society, and becomes a vigilante who steals from the rich.

Chun Dung who grew up in a beggar's quarters (although born as a noble) with no knowledge of his parents, dreams of "making this world a better place" by taking part in the peasants’ riot while Gwi Dong who was raised in a noble life (though he was born as a beggar), serves as a police official, fights against corruption within the government and speaks for the weak.

[2] The background of the drama is not set in a grand palace but an everyday market and talks not of the success of a great hero but the agony of common people.

The Duo portrays the everyday lives and loves of the commoners and outcasts during 19th century Korea: Slaves, beggars, leather shoemakers, thieves, street bums and butchers, people who were poor yet good at heart.