My father remarried another woman, so suddenly I had a new mother and a younger sister. I was extremely nervous, worried, and trying to figure out how to be a good older brother. But when I met my new younger sister, I was deeply disappointed. She seemed to be a rebellious teenager, very unruly, selfish, and stubborn. I really don't know how to live with this person anymore. When she came home drunk, she accidentally entered the wrong room and ended up sleeping in the same bed as me. I suddenly woke up and saw her face right next to me, my penis involuntarily reacted to her cute face that she normally didn't show. Unable to resist, I touched her all over her body, accidentally waking her up. Although she said to stop, through her reaction, I knew she was also feeling extremely excited and pleasured. I went further and had sex with her. And from then on, our twisted relationship began...