The continent of Usea was struck by an asteroid, causing the death of half a million people. The neighboring Erusea used this as an opportunity to invade and occupy almost all of Usea. Based on its eastern coast, the Independent States Allied Forces (ISAF) try to regain ground an engage the Eruseans in aerial battles. An elite pilot using the codename Mobius 1 is sent on a number of missions to fight Eruseans and help ISAF to win the war. While performing those missions, Mobius 1 begins to learn about the impact war has on civilians, and the pilots of the opposing side.