Sister-sama no Oose no Mama ni

One day, the demon Clod comes to high school student Sister Kris Ibarakawa. He says that he has a contract with Kris\'s estranged father to make her happy. He is very serious even for a demon, and says, \"I will definitely make you happy,\" and uses various kinds of magic... Will Kris be able to follow the path of a pure and righteous sister?