Mako, a daughter who came to her parents' house to help with housework because her mother was hospitalized due to illness. While chatting with her father, her younger brother comes home, but his attitude is somewhat unfriendly. Mako, who was interested in her, looked into her room and found that her brother had purchased a masturbator. Mako realizes that he is a virgin because he doesn't know how to use her, and she teases him, but she is pushed down by her adolescent power. From that day on, she would be fucked by her brother's libido.
