Aoi is of a certain age and is popular with boys because of her Ke'ai , laughter and good personality. Although she just broke up with her current boyfriend, she already has a new one. Her brothers, who have always Ke'ai , are jealous and deeply in love with her and begin to desire Aoi body. Although Aoi knows that it is wrong for siblings to have a physical relationship, her feelings of immorality and guilt only increase her arousal, and she becomes addicted to the pleasure of having sex with her brothers.