For years, the world government had kept a secret: mythical creatures such as centaurs, mermaids, harpies, and lamias are real. These creatures living among us, hidden in the shadows… Until now. 27 years ago, the government revealed the existence of these creatures and passed the "Interspecies Exchange Bill". Since then, these creatures, which have now become to be known as "Liminals", have become a part of human society, living with ordinary families like foreign exchange students and au-pair visitors, but with other duties and restrictions (the primary restrictions being that Liminals and humans are forbidden from harming each other or procreating). The story follows the life of a young man named Kimihito Kurusu, who's life had changed after he accidently giving the responsibility of taking care of a Lamia named Miia five years ago. Now the man of the house, Kimihito has now gotten used to having Miia and is happy to have her. Unknown to him, his life is about to change once again.
Sorry I didn't put this summary in, you guys know how it is. Little heads up, this story will also contain the characters of Kill La Kill (from a alternate universe storyline similar to the original) from the Mystic Dragon Force series.