The target of hitgirl Mikura is a wealthy baseball team owner, but he turns out to be a powerful underworld boss. Mikura and her team are beset by countless heavily armed bodyguards and the boss' vicious daughter.

In 2100, the newly built Bayside City serves as Japan's premier international port. The Angel Arms Company is established by a former policewoman named Takako, to help wage war on terrorism with armed security suits. When the mayor is assassinated, the women of Angel Arms end up protecting the evil crime-lord Hassan, in hopes that his information will help bring down a global terror ring. Takako's back is to the wall as a band of criminals plot to kill Hassan, and the organization's leader is revealed to be the former lover of Angel Arms' own Alisa.

Japan, ten years after World War II. Boy detective Shotaro solves mysteries and fights crime with the help of Tetsujin 28, the 50-foot tall giant robot left for him by his late genius father. But one day he's shocked to learn that his father also adopted and raised another boy named Shotaro, now a repatriated soldier. Just as surprising to our young hero is the fact that his “big brother” can also control Tetsujin, even better than he can. But with the emergence of this elder brother comes danger, as a mysterious assassin, Morning Moon, closes in on the boy for being unworthy of controlling the robot. Meanwhile, the capital faces destruction when multiple bombs are discovered, planted by the two Shotaros' father himself!