The story of a young karate practitioner. Source: My Anime List

In the late 1990s, society is descending into ecological collapse and totalitarianism. Saiga Rikioh, 21, finds himself in jail. Set in the near future, at the privately-owned Tokyo State Prison. Like the chilling wind of the end of a century, a mysterious man with a six-pointed star on his fist entered the pen. Saiga Riki-Oh--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.