When I was still a student, my older brother brought Aika home to introduce her to the family. Aika was an incredibly cute and beautiful girl, especially her big boobs that I couldn't take my eyes off! I felt jealous of my brother for having such a good girlfriend. Hearing the sounds of them fucking in the next room made it so difficult for me to control my arousal. Some time later, Aika is now my sister-in-law, and I have graduated and started working. This time, during a business trip to Tokyo, my brother invited me to stay at his place for a few days to save on hotel expenses. So after many years, I finally got to see Aika again. She was still as cute and beautiful as ever. However... she wasn't wearing a bra! I could see her nipples poking out and the shape of her round boobs! Especially when I found out that my brother was working overtime constantly and not having sex with her, I couldn't bear it anymore! I couldn't let a seductive body like this go to waste! At first, she resisted, but after realizing the affection and enjoying the pleasure that my cock brought, she started actively joining me. And so, during the time I stayed here, I took care of my beautiful sister-in-law instead of my brother...