A college student otaku male started living alone due to advancing in his studies. His sister, envious of her brother, began frequently entering and exiting his room. One day, the sister tried to negotiate using her brother's room as a place to have sex with her fuck buddy but was rejected because her brother said friends were coming over. The troubled younger sister suddenly came up with an evil idea and decided to execute it… As she mentally cornered her own brother, she discovered a sadistic tendency. She mocks the brother whose friendship was destroyed and turned into a masochist.
