I live alone in Tokyo and my life with my sister (Kokoro) suddenly began in my very small apartment. Kokoro, who has suddenly turned into big breasts, is extremely insecure at home and is always in a position to play polo, so she is troubled with the question of where she should get examined! I couldn't stand it and forced myself in... However, that night, "I was rough all the time..." And this time, he took a pill to the heart and asked to have sex! ? We have a secret relationship that we never told our parents about.