The story starts four years after Operation: Black Eden, where the United States is the last nation standing against the Chimera, but leaving most of the states into barren wastelands along with the rest of the world.
Learning that the Chimera have opened a wormhole to freeze Earth and eradicate the last of humanity, Joe Capelli sets out on a treacherous journey across the ruined United States in a last-ditch effort to end the war and save the world once and for all.