A geeky college student starts living alone after entering college. His younger sister, jealous of him, begins to frequent his room. She negotiates with her brother to borrow his room so they can have sex, but he refuses, saying that his friends will be coming over. At a loss, the younger sister suddenly comes up with a diabolical idea and decides to put it into action... As she tortures her brother, she awakens her sadistic tendencies. She laughs at her brother, whose friendship has been destroyed and who has been turned into a masochist.