Several years ago, Earth was struck by a colossal meteorite, leading researchers to discover a mysterious alien capsule called the "black box." To investigate its contents, an international organization, known as "Project BB," was established. Near the headquarters of Project BB, Manabu Yoshimura and seven other students from the International Academy attended a nearby school. Their instructor, Toukichi Hashiba, proposed an experiment that would earn them class credit, requiring them to enter into the vacant chambers of the meteorite. Hashiba anticipated that the strong willpower of humans would unleash a response from the meteorite. If they envisioned a robust, mammoth robot, something would undoubtedly occur. Unexpectedly, a spaceship presented itself in the sky, and a 3-D image of an alien named Wercury appeared. He hailed from the Star of Prokimasi and had come to gather the Choshin people's meteorite. If they refuse to relinquish it, he would challenge them to a fight. Manabu and his peers were taken by surprise with this unforeseen twist of events. Nevertheless, the meteorite responded to their collective will, transforming itself into a massive robot. They battled a Prokimasi robot and were compelled to unite and defend themselves. However, the group struggled to synchronize their intentions, leading to the robot's limited battling effectiveness. Would Manabu and his comrades be able to guard Earth and the meteorite against Prokimasi's attack, with the aid of Hashiba's "Gakusaver" robot?