Having the opportunity to have summer vacation, international student Sakurai decided to book a plane ticket to return home to visit her family. The first person Sakurai saw when she opened the door was her younger brother Riho Fujimori, Maybe because she thought she was an adult, when her sister patted Riho Fujimori's head, she immediately pulled her hand away and looked uncomfortable. Abroad, Sakurai was quite promiscuous, so she met a lot of western guys, and when she got home, no one fucked her anymore. So she often feels itchy "there", and the older sister firmly believes that Riho Fujimori is the only man in the family who can satisfy her. Sakurai watched her younger brother As a sexual tool, the girl constantly found ways to make Riho Fujimori want to fuck her. Although she knows that as biological sisters, this is against morality, but in truth, Riho Fujimori cannot resist the attraction of her beautiful sister's body...