WANZ-924 Playing cards and taking off clothes with your girlfriend's sister Mizuki Yayoi.

While I was at my girlfriend's house, through the dim and blurry crack of the door, I saw a girl in a bikini sleeping in front of me. Her body resembled that of my sultry girlfriend. I thought it would be enjoyable to have relations with her unexpectedly, but to my surprise, it was my girlfriend's sister.