During the final days of World War II, the Japanese military was secretly developing a superweapon intending to help save the Japanese Empire. After twenty-seven failed attempts, Dr. Kaneda completed a three-story high, remote-controlled robot. The robot was officially named Tetsujin 28-go. The war, however, has already been over, and Dr. Kaneda died of heart failure shortly after completing Tetsujin 28. Rather than becoming the military's key weapon, Tetsujin 28 was given to Dr. Kaneda's ten-year-old son, Shotaro. Under Shotaro's control, Tetsujin is put to work stopping criminals and enemy robots.