When an extraterrestrial organism known as "Savage" attacks mankind, the only technology capable of combating the enemy is a weapon known as “Hundred.” A survivor of a Savage attack, Hayato Kisaragi is a teenager boasting the highest compatibility level with the aforementioned technology and as a result, is invited to master his skills at Little Garden, a prestigious military academy aboard a battleship. Over the course of his intense training for the battle ahead, he immediately attracts the interest of multiple female peers and gets drawn into a number of incidents as he tries to fight against the creatures that now inhabit Earth and threaten its safety. [Written by MAL Rewrite]

The girls are saved ... by none other than Catty Nebulart herself! Now, the race is on as Catty struggles to complete her crowning achievement: a huge machine that will bring life to a lifeless world!

The year is now 2041 AD. A new enemy called Zeravire suddenly appears in the solar system, destroying all military installations it comes across. However, a wealthy man named Klein Sandman is already aware of this planned invasion and had been secretly preparing his army for battle. His trump card is Gravion, a giant robot that utilizes gravity as its source of energy. Meanwhile a young man named Eiji secretly enters Sandman's base in search for his missing sister. It is there that he meets another young man by the name of Toga... These two must now fight together with four other individuals aboard the super robot, Gravion to fend off the Zeravire threat.

The pilot Sue Harris goes to a mission on a frozen country, there she suffers an accident on the mountains and her life is in severe danger. Trying to survive on the harsh enviroment, she encounters an alien and engages in combat with it. The two beings will use all means possible to escape of that dead trap alive.