Three years ago, the world learned that harpies, centaurs, cat girls, and all manners of fabulous creatures are not merely fiction; they are in fact of 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 are 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. Unfortunately for Kurusu, Miia is undeniably sexy, and the law against interspecies breeding is very strict. Even worse, when a flirtatious harpy named Papi and a ravishing centaur girl, Centorea Shianus, move in, what should a teenage human with raging hormones do?!