The solar system falls victim to invasion by the Kikaika Empire, swiftly conquering Neptune, Uranus, Saturn, Jupiter, and Mars, and setting their sights on Earth. Yet, a formidable obstacle arises in the form of Eldoran: a legendary guardian and luminary warrior. In response to the threat, Eldoran endows a group of fifth-graders with three gargantuan mechanical dinosaurs that unite into the formidable Gosaurer. These young students take charge of Gosaurer and wield its strength to impede the Kikaika Empire's encroachment.