Following the events of Ace Combat 04 and Ace Combat 5, the Osean Federation brokered peace between the military power of Erusea and the rest of the Usean continent.
Setelah kejadian Ace Combat 04 dan Ace Combat 5, Federasi Osea menengahi perdamaian antara kekuatan militer Erusea dan seluruh benua Usea.