A ravaged Earth struggles to survive after a nuclear holocaust has left the world in ruins. Survivors band together in communities and villages, living off what little resources remain. In the wastelands beyond, vicious gangs prey on the survivors for their resources, or sometimes merely for sport. A mysterious martial artist named Ken, a man with seven scars on his chest and the chosen successor of the legendary assassin's art Hokuto Shinken (The Divine Fist of the North Star) has sworn to protect the weak and innocent from the malicious gangs roaming the scorched planet.