In the year 2090, the world's conflicts are fought using giant war machines called Wanzers. Huffman Island, the only place where the Oceania Cooperative Union (O.C.U.) and the Unified Continental States (U.C.S.) share a land border is a hotbed of conflict. An O.C.U. reconnaissance platoon led by Captain Royd Clive is assigned to investigate a U.C.S. munitions plant. They are ambushed by U.C.S. Wanzers, triggering a series of events that plunges the whole island into war.