... so named because man has expanded into outer space, founding space colonies. For decades the colonies remained a place of peace while the Earth was torn by war. When the wars on Earth settled, the "United Earth's Sphere Alliance" took control and also seized control of the peaceful colonies. The colonies' leader and representative to the Alliance, a man named Heero Yuy, lobbied for demilitarization and pacifism and was well-recieved by colonist and Earth citizens alike. Perhaps those in power felt that a leader promoting peace was a threat to their plans for the colonies. Heero Yuy was assasinated in the year AC 175.

It is believed that an organization within the Alliance, known as OZ, was behind the assasination of Heero Yuy. The colonies were thrown into a state of turmoil, until the Alliance restored order through excessive military intervention. All communication between the colonies was prohibited from that point on. Even Earth-bound nations such as the pacifist Sanc Kingdom, which promoted Heero Yuy's ideals were attacked and destroyed by the Alliance as an example to all others who might oppose them. For two decades the Alliance use their powerful military weapons, called mobile suits, to keep the colonies under their control.

After twenty years of being oppressed, a group of rebels strike back at Oz, in order to get reveng for the death of Heero Yuy, and to free the colonies from the Alliance. Five immensely powerful mobile suits made of gundanium, a nearly indestructable metal, are built and sent to Earth disguised as meteors from different colonies. Each of these suits, called "Gundams", is operated by a highly skilled, though very young pilot. These young men have all been trained from a very young age to be ruthless soldiers. They each have a very unique past and distinct personality. Not one of them is aware of the existence of the other Gundams, or the other pilots.

And this is where it all begins...