That JAV

A university student geek male who started living alone when he went to college. Envious of such a man, the younger sister begins to frequent her brother's room. She negotiates with her boyfriend to rent the room as a place to have sex, but he refuses because his friends are coming over. The troubled sister decides to carry out a diabolical idea that suddenly occurs to her.... As she pushes her brother to the edge mentally, she awakens her proclivity to be a sadist. She scoffs at the sight of her brother, whose friendship has been destroyed and turned into masochism.