Showa American Story is an open-world action-adventure RPG with a third-person view in a post-apocalyptic setting. Japan bought out most of the United States due to its strong economic power. The surge in immigration firmly rooted Japanese culture in the Americas. The two cultures quickly merge, although sometimes there are conflicts, but the citizens gradually adapt to a life they never imagined. However, a mysterious disaster radically changes the world. There is no social order for a long time, and the world has plunged into chaos and destruction. But one day, a young girl mysteriously comes back from the dead and discovers a completely new wild post-apocalyptic world with zombies, monsters and survivors of different persuasions.