Jiwon had a long-standing unrequited love for her childhood friend, Jinho. She wanted to confess her feelings to Seo Jinho, but the person he liked was none other than her own older sister! One day, Jiwon, who had continued her bitter unrequited love, stopped by her house with Seo Jinho and heard the news of her sister's marriage. "Did you know my sister was getting married?" "...Yes." Seeing Jinho, who looked hurt, Jiwon's heart also ached. Just as she was about to comfort Jinho, the two ended up spending a night together by accident. Jiwon harbored complex feelings for Jinho, who had slept with her seemingly without meaning to, and tried to avoid him and run away, but... "So... you weren't in love with my sister?" "That's right. How many times do I have to tell you? The one I like is you."