My dream came true and I started dating my girlfriend, a member of the swimming team, who looks great in her short hair and competitive swimsuit. However, when we are alone, she has a harsh personality and always looks down on me, insulting me and using me as a toy, and before I know it, I am being trained by a masochistic man. At first glance, she looks slender, but in fact she is a beautiful, athletic girl with hidden muscles, "Ai Mukai", and her first "Sadistic Girl" role is sure to thrill the hearts of masochistic men.