I had a sexual relationship with my girlfriend's older sister for six months. Every time we met, we would have sex. (Hasegawa Yuna ADN-505)

Looking back, I think I started to have feelings for her from the first time I was introduced to her (Akane). Today is my older sister's (Mayu's) birthday, and after hearing the news, I couldn't sit or stand. Suddenly, I found myself at my sister's doorstep. I rang the doorbell, but there was no response. Just as I was about to leave, my sister came out. Ah, so I do like her. My feelings are now clear.