In Showa 66 (1981), Japan has almost bought out the entire United States with its formidable economic power. With a massive influx of immigrants, Japanese culture has taken deep root in the American continent. The United States, once a global leader, has now become an unofficial colony of Japan, with the two cultures rapidly merging.
However, a mysterious catastrophic event has completely changed the world. Social order has collapsed, zombies and monsters roam the streets, and survivors are fighting over scarce resources. Amidst this chaos, Chouko, a 19-year-old stuntwoman, is mysteriously revived. She finds herself in a new world filled with zombies, monsters, and various survivors.