Takasugi Mari lived with her stepfather and stepbrother because of her mother's remarriage. The stepbrother happened to go to the same school with her. The gentle step-brother gradually reveals his nature in the cohabitation life. Masturbating to the sleeping girl, she couldn't suppress her sexual desire and ran into the night. Regardless of people in school, work hard 24 hours a day! Let her brain resist, but her body is straight to the top!