A gigantic meteorite landed on earth a few years back. A mysterious capsule believed to have belonged to the aliens was discovered. Called the "black box," an international organization called "Project BB" was created to research it. Eight boys, including Manabu Yoshimura, attend International Academy, a school located near Project BB headquarters. They are enticed by their teacher Toukichi Hashiba's promise of "I'll give you class credit," and end up getting involved in his experiment. The experiment was to enter the eight empty chambers of meteorite. According to Hashiba's theory, the meteorite should strongly respond to strong human thoughts. He tells them to have a clear image of a great looking gigantic robot; if they do, something should happen... Then, a big spaceship appears in the sky and an alien calling himself Wercury appears in a 3-D image. He tells them he is from the Star of Prokimasi and that he has come to collect the meteorite of the Choshin people. If they do not hand it over, he will challenge the earth beings to a battle. Manabu and his friends are confused by the unexpected turn of events but the meteorite responds to the thoughts of the group and suddenly starts to transform itself into a gigantic robot. Then, attacked by the invading Prokimasi robot, they are forced to pull their strength together and fight back. But it is extremely difficult to put the wills of the eight together as one and the robot cannot fight in the way it should. The gigantic robot that Hashiba named "Gakusaver" and Manabu's eight; can they manage to protect Earth and the meteorite from the Prokimasi invasion?

The science lessons are short "omake" bonus features originally present on the first two volumes. Each short lasts around two minutes, and stars super deformed versions of Noriko, Kazumi and the Coach explaining the various scientific aspects of the series.

In the near future, humanity has taken its first steps towards journeying into the far reaches of the galaxy. Upon doing so they discover a huge race of insectoid aliens known as "Space Monsters." These aliens seem dedicated to the eradication of mankind as they near closer and closer to discovering Earth. In response, humanity develops giant fighting robots piloted by hand-picked youth from around the world. Shortly after the discovery of the aliens, Noriko Takaya, the daughter of a famous deceased space captain, enters a training school despite her questionable talents as a pilot. There, she meets her polar opposite, the beautiful and talented Kazumi Amano, and is unexpectedly made to work together with her as they attempt to overcome the trauma of war as well as their own emotions.

New York City, the late 1920s. The battle with Nobunaga is over, the city restored to peace...until the owner of Little Lip Theater informs Shinjiro... "This time, the leading lady will be...you." Thus Shinjiro, disguised as the actress Petitmint, is forced into the role of "Cleopatra." The Star Division members set out to persuade a reluctant Shinjiro, beginning a chase across the five boroughs. Meanwhile, a dark-skinned youth and his servant have appeared unexpectedly in the midst of the flourishing city. His eyes, concealing a silent wrath, are fixed upon nothing less than the Statue of Liberty. Now Shinjiro and company must protect this city of hopes and dreams from a new menace while safely raising the curtain on a new show.