While sleeping one night, Ryo Utsugi had a nightmare of monsters attacking him. One day he learns a mysterious power to let him hear voices and have visions of girls getting killed, but one night he hears the same voice.

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.

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!