Elementary school children take control of giant robots to save the earth from the evil Jaku Empire.
Suddenly, an evil empire Jaaku raids the Earth. But the light appears from the Earth, and fights against Jaaku. It is Raijin-Oh operated by Eldran. Eldran has protected Earth since the ancient ages. He was injured during the fight, however, and Raijin-Oh falls to the ground. On the other hand, Jaaku scatters their weapons, Aku Darmer, all over the world.
Meanwhile, in Yosho elementary school, they have extra lessons in the 3rd class of the 5th grade. Eldran leaves Raijin Medal to them and asks them to save the Earth for him, and then he disappeared. In this way, the Earth Defense Agency consisted of elementary students is founded.
