His older brother Ryuta is a semi-withdrawal and had a sexual relationship with his younger sister Nenne. She knew it was wrong, but she couldn't refuse Ryuta, who was kind to her. continue to have sex. One day, Ryuta's friend from school, Kameda, comes to visit. Kameda took notice of Nenne's big breasts, threatened her relationship with Ryuta as a joke, and planned to lay down her nene...
