Rokurou is a self-proclaimed "defender of my home" (in other words he's a hikikomori, and an eroge otaku to boot). One day, when he is at a book store, he meets a girl, Sara. She follows him around and finally comes to his house. "I'll be in trouble if my parents know it..." It looks like she never leaves. "This is why I don't like 3D girls..." He tries to get rid of her, but Sara always sexually seduces him... Will he be able to bear his libido and her sexual advances...?