The Joseon era in 1724 was shrouded in endless party struggles, and the national situation was in chaos. In the Myeongwolhyang brothel located in the center of Hanyang, there was a beautiful and artistic courtesan, Seol-ji (Kim Ok-bin), who was known as the "No. 1 Geisha in Pyongyang". Cheon-dong (Lee Jung-jae), a gangster who fought and made trouble all day, fell in love with Seol-ji at first sight. However, Man-deok (Kim Seok-hoon), the backstage owner of the Myeongwolhyang brothel, also wanted to take Seol-ji for himself, but found that Seol-ji and Cheon-dong were already in love, and Man-deok secretly had murderous intentions in his heart. Cheon-dong dreamed of becoming the "No. 1 Iron Fist of Joseon" since he was a child. One day, he fought with someone casually as usual, but he didn't expect that the person he accidentally defeated was the "unbeaten god" of Joseon's fist world-Du'er. Cheon-dong rose to prominence and became a temporary big brother, which instantly gave Cheon-dong the capital to compete with Man-deok for Seol-ji. Between Cheon-dong and Man-de, a fight full of jokes officially took place...