While pursuing a vicious pistol-wielding robber, Detective Hachiro Azuma, a skilled detective with the Tokyo Metropolitan Police Department's First Investigative Division, falls into an enemy trap and suffers mortal injuries. He is treated by the mysterious scientist Dr. Tani and awakens once again. However, his body is no longer usable, and he is reborn as a robot, replicating his memories and personality from his previous life. He is reborn as "Eight Man," a super robot equipped with a miniature nuclear reactor hidden in his chest and possessing numerous supernatural powers.