In the aftermath of World War II, a defeated Japan struggles to rebuild. A secret weapon, developed too late to change the war's outcome, is unearthed: Tetsujin 28-go, a massive, remote-controlled robot of immense power. The robot falls into the hands of a young boy detective, Shotaro Kaneda, who was bequeathed the control box by his late father, one of the robot's creators.

The live-action television series from 1960 adapts this core premise but makes significant changes due to production constraints and creative direction. Instead of a towering twenty-meter giant, the robot is portrayed as a two-meter tall suit, essentially a man in a robotic costume. The scale of the threats is reduced accordingly, shifting the focus from city-wide catastrophes to smaller-scale criminal and military operations. The setting is a contemporary 1960s Japan, blending the era's optimism with the residual shadows of its recent militaristic past.

Shotaro is the central protagonist, a resourceful and courageous boy who works alongside the Japanese Self-Defense Force and the industrialist Professor Shikishima. In this version, Shotaro is not Dr. Kaneda's son, though he remains the robot's primary operator. He is often aided by the warm-hearted and enthusiastic Chief Inspector Ootsuka of the Tokyo Police, who acts as a father figure and close ally. Together, they form a team dedicated to stopping the rise of new threats, most notably the shadowy terror organization known as QX.

The primary narrative arc revolves around the battle against QX, a group that seeks to exploit leftover military technology and build their own robot weapons to terrorize Japan and seize power. Unlike later adaptations that explore heavy themes of war guilt and the robot as a symbol of Japan's destructive past, this 1960 series treats Tetsujin 28-go more directly as a superheroic tool for justice. Shotaro uses the robot to combat QX's schemes and the various giant robots they deploy, such as the formidable Black Ox, which is often controlled by the reclusive mad scientist Dr. Franken. The series follows a mostly episodic monster-of-the-week formula, with Shotaro and his allies facing a new robotic threat in each installment while the overarching conflict with the QX organization simmers in the background.