When the nefarious Jaaku empire launches a sudden attack on Earth, a beacon of light emerges from the planet to combat the threat. This light takes the form of Raijin Oh, a mighty robot piloted by the ancient protector Eldran. Despite Eldran's valiant efforts, he sustains injuries in battle, causing Raijin Oh to crash to the ground. Simultaneously, Jaaku scatters their destructive weapons, the Aku Darmer, across the globe. Meanwhile, at Yosho Elementary School, a group of students in the 5th grade's 3rd class find themselves in an unexpected situation with extra lessons. Entrusting the Raijin Medal to these students, Eldran vanishes, tasking them with the mission to save the Earth in his absence. Thus, a unique Earth Defense Agency is born, comprising elementary school students determined to defend their planet.