Riki finds himself in the town of Misaki, dotted with illegal nuclear power plants and run by a religious fanatic military organization called "God's Judgment." He is taken prisoner and made to fight in gladiatorial matches in a sprawling arena. He finds his brother, whose special powers have given him the name of "Savior," but his reunion with his resentful sibling turns sour rather quickly.

In the late 1990s, society is descending into ecological collapse and totalitarianism. Saiga Riki-Oh, a mysterious man with a six-pointed star on his fist, finds himself at the privately-owned Tokyo State Prison. Serving a term of three years due to assault, his first offense, Riki-Oh openly antagonizes The Four Emperors, four powerful prisoners that control the prison and keep the rest of the inmates in line...