FPRE-231 Big-breasted older sister Aoi Ebisaki is gang-raped by boys and used as a sex toy by the neighborhood association in order to protect her younger brother.

Aoi and Jun, sisters who have just started a new life at their maternal grandparents' house. Their father has passed away, their mother is hospitalized for a long time due to illness, and their maternal grandparents are in a nursing home, so they have moved into the grandparents' house which has become vacant. Jun has been timid and easily bullied since he was little, and soon after moving in, he is targeted by the neighborhood bullies. "I will protect my brother no matter what!" With that thought in mind, Aoi finds herself confronting the boys...