Ace Combat 5

Ace Combat 5: The Unsung War takes place in the year 2010. According to the game's backstory, war had previously broken out in the game world in 1995, fifteen years prior to the events of the game. In this war, detailed in the game's prequel Ace Combat Zero: The Belkan War, the bellicose nation of Belka aggressively attacked its neighboring countries in an expansionist manner. The war turned against Belka, however, and the nation faced defeat under the combined forces of the superpowers Osea and Yuktobania, along with other nations. In response, Belka set off seven nuclear weapons on its own cities in order to stave off the advancing enemy. Following this catastrophe, the opposing nations vowed to disarm. In the war's aftermath, the former state of South Belka became a protectorate of the Osean Federation, although Belkan citizens remained hostile to Osean occupation.

The player character is a member of an Osean Air Force squadron stationed on Sand Island, located on the ocean which separates Osea and Yuktobania. Although initially thought of as an island isolated from civilization, Sand Island serves as a front line during the events of Ace Combat 5 after the "fragile peace" established between Osea and Yuktobania during the previous war comes to an end.