Monster Musume revolves around Kimihito Kurusu , a Japanese student whose life is thrown into turmoil after accidentally becoming involved with the "Interspecies Cultural Exchange" program. A PC game based on the series was released in December For years, the Japanese government had kept a secret: mythical creatures such as centaurs , mermaids , harpies , and Lamiais are real. Since then, these creatures, 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. In Asaka, Saitama , Kimihito Kurusu did not volunteer for the exchange program. But when Kuroko Smith delivered the very scared and embarrassed Miia to his door by mistake,  he did not have the heart to send her away and they started living together. As the story continues, Kimihito meets and gives shelter to other female liminals, each of a different species.