Yuusan was my senior in school, a classmate of my older brother. Unlike my brother, who was shy and not very impressive, Yuusan was kind to me. I always had a one-sided crush on him... But I never expected him to marry my brother... I'm living with my brother's family for job hunting, and my feelings are complicated. After the letter I wrote back then, expressing my feelings for Yuusan, which I never got to give him and never threw away, was discovered, I ended up having unprotected sex with Yuusan many times...