東京のアパレルショップで働くちとせは連休を利用して実家に帰省していた。しかし、顔を出さない弟のヨウタが心配になり両親に話を聞くと、何でも女の子にフラれ学校にも行っていないという。それならばと、ちとせは再び女の子に興味を持って貰う為ノーブラ爆乳を見せつけてヨウタを元気づけようとするのだが、ヨウタの眠っていた異常な性欲を目覚めさせてしまい、猿の様に求める超絶倫弟に追い回されハメられまくるのだった…。
Chitose, who works at an apparel shop in Tokyo, went back to her parents’ home during the long weekend. However, she was worried about her younger brother Yota, who hadn’t come over, so she asked her parents about it. They told her that he had been dumped by a girl and wasn’t going to school. So Chitose tried to cheer up Yota by showing off her huge breasts without a bra in order to get girls interested in her again, but this awakened Yota’s dormant abnormal sexual desire, and she was chased and screwed by her super-horny brother who wanted her like a monkey…

– JavGG.net