The story of Fist of the North Star is set in the year 19XX after the world has been devastated by a nuclear apocalypse, leading to the near-extinction of humanity and the collapse of nations. The entire world is now ruled by violence. The surviving humans are divided into two factions: the strong, who possess power and continuously engage in robbery and slaughter, and the weak, who are subjected to brutal torment.

As the weak find themselves on the brink of despair, a man clad in tattered clothing, bearing a scar on his chest in the shape of the Big Dipper constellation, steps forward. He is Kenshiro, the successor of the martial art known as "Hokuto Shinken" or "Fist of the North Star." Kenshiro challenges numerous formidable enemies on his own, becoming a beacon of hope for the oppressed and a force to reckon with in this post-apocalyptic world.