Twice in the last century, brutal war erupted between the United States and the Confederacy. Then, after a generation of relative peace, The Great War exploded worldwide. As the conflict engulfed Europe, the C.S.A. backed the Allies, while the U.S. found its own ally in Imperial Germany. The Confederate States, France, and England all fell. Russia self-destructed, and the Japanese, seeing that the cause was lost, retired to fight another day. The Great War has ended, and an uneasy peace reigns around most of the world. But nowhere is the peace more fragile than on the continent of North America, where bitter enemies share a single landmass and two long, bloody borders.