Set in October 2112, the story of Front Mission 3 takes place in Southeast Asia, revolving around the Oceania Cooperative Union (OCU) and the People's Republic of Da Han Zhong (DHZ). Since the People's Republic of Alordesh won their independence from the O.C.U. in 2102, member-states within the union also formed their own separatist movements. Countries such as Indonesia and Singapore began voicing their anti-OCU sentiments, both through peaceful and non-peaceful means. In 2106, pro-nationalist forces in the Philippines wage war on the government and their OCU handlers. Desperate to maintain stability in the region, the O.C.U. Central Parliament allows the United States of the New Continent (USN) to send in peacekeeping forces to resolve these conflicts. Eventually, the supranational union is pushed to the breaking point in 2112 when a mysterious explosion occurs at a Japanese Defense Force (JDF) base in Japan.