In Japanese-occupied South Korea, a young man, newly-released from prison, is accepted into a gang for his fighting skills and quickly rises to the top. Based on the life of South Korean mobster and politician Kim Du-han.

Upon being released from prison, Kim Du-han begins rebuilding his street gang in the face of Hayashi's Yakuzas and increasing Japanese influence.

Following the final events of General's Son 2, Kim Du-han is forced to go on the lam but eventually returns to Jongro where he attempts to rebuild his gang with the brothers that are still alive and loyal and defeat Hayashi's Yakuzas once and for all.