Two military forces, Gion and the Federation are at war, as a soldier your fate is governed by circumstances which has nothing to do with your own will, so board your mobile suit, pick up some firearms and go to war.
There are two main modes of the game, the single mode and the multi-mode. The single mode is something like a practice mode where you travel across the world and take part in all sorts of missions. You are not allowed to choose your mobile suit for these missions, you can only take what is provided for you. These missions include attacking enemy bases, taking over the enemy's mobile suits and even open warfare.
After you have completed the single mode, its time to take on all the veteran pilots out there. A maximum of 10 players can participate in a multi-mode game through the Xbox360's. The ten of you can either split into two sides and make war against each other, conquer the territories of your opponents or get involved in an all out brawl where the single mobile suit that comes through the chaos is the victor.