A kid inherits a giant robot and a dead father's unfinished war. The machine is a miracle of engineering and a monument to atrocity, built on blood that no one wanted him to know about. Watching Shoutarou learn what his father's mentor actually built, and what that machine cost to create, is watching a child discover that every person he trusted has been lying to protect him from the truth. The robot doesn't save Japan. It forces Japan to reckon with itself. That's the show working, not the action, but the weight of what power means when it's built on graves.

In post-war Japan, Professor Shikishima has built Shikishima Industries into a technological powerhouse focused on robot development. Behind that success lies a dark secret from World War II, one that cost the life of his mentor, Professor Kaneda. During the war, Japan pursued a covert project to create giant robots as weapons, and Kaneda managed to complete the 28th Tetsujin. Years later, young Shotaro Kaneda is chasing the mischievous Murasame brothers when a giant rocket headed for Tokyo lands in front of them and opens to reveal a giant robot. Kaneda's son now stands on the edge of learning what really happened, a truth that will leave him permanently changed.