Ellen, who attends a university student in Tokyo, returns home after a long time, but she doesn't have a conversation with her adolescent brother and Ellen feels a little lonely. One day, she happens to find an erotic book in her younger brother's room, and Ellen shows off her no bra huge breasts to make fun of her as a child, but she awakens her younger brother's sleeping libido. When the huge breasts are roughly rubbed and inserted, it is vaginal cum shot in quick succession and it is chased by the transcendental younger brother from that day.