Shuji lives a peaceful life with his younger sister, Saki. But he secretly lovesher and his libido gets uncontrollable day by day. One day, Saki tells him, "Ilove you.... I've been always thinking about you since I was a kid...." Likethis, they become boyfriend/girlfriend. However, their happiness is destroyedby an email. "I know your everything...." The email attaches a photo of Sakichanging clothes and masturbating. Saki thinks her stalker did it. The stalkergives her various immoral orders. She first tries to resist it, but she graduallygets addicted to it.... Well, will Shuji be able to save Saki...?