Tokyo, 1996. A demon invasion and a coup carried out by an unknown man plunge the capital into chaos, transforming it into the demon city. A resistance group called the Partisan rises up against the occupying power, but the conflict quickly spirals past anything they can contain. At its core is a crisis of parallel universes and fractured timelines, and the player—acting as Naoki—must make pivotal decisions that determine which path history takes and what kind of world survives.