Three years ago, the world learned that harpies, centaurs, catgirls, and all manners of fabulous creatures are not merely fiction; they are flesh and blood - not to mention scale, feather, horn, and fang. Thanks to the "Cultural Exchange Between Species Act," these once-mythical creatures have assimilated into society, or at least, they're trying. When a hapless human teenager named Kurusu Kimihito is inducted as a "volunteer" into the government exchange program, his world is turned upside down. A snake-like lamia named Miia comes to live with him, and it is Kurusu's job to take care of her and make sure she integrates into his everyday life.