After the public rates the judicial system corrupt, the Devil Judge is appointed to live stream his trials. A reformist judge is hired as a secret mole to keep an eye on him.

Ancient Korea, 1728. Swordsman Kim Ho, guard of King Yeong-jo of Joseon, is demoted and sent to work in Uigeumbu prison. When night falls, the prison is assaulted by the master warrior Do Man-cheol and his powerful henchmen for the purpose of freeing Lee In-jwa, who has been condemned to death for rising up in revolt against the king.