Scenario

You need to choose scenario before starting the game. Scenario determines map layout, factions, characters, situations and so on.

Plot of each scenario
There are some scenarios by default:

Enemy in family (敵は一族の内にあり)
The scenario starts from war between A family and T family.

Warlords Divided (群雄割拠)
After leader of A family Athrun died, all of A family members occupy their planets, with ambition of conquer. T family members also divided into two countries.

Resurrection of Japan (ジパングの復活)
After Puggle(パグン) died, Beta who becomes next overlord of Puggle's country, proclaims himself as Tenno, states that an old country names Japan just back, and invites anyone who associated with Japan to build this country. As a result, a strong country rises in central...

The final conqueror (最後の覇者)
With years passed, there are only six countries now. They are going to have the final war, to decide who is the final conqueror in this universe.