I have a very lovely girlfriend. Lee Hayeon. My girlfriend and childhood friend who stayed by my side for 10 years. I first met Hayeon when I was so young I can't even remember it now. Blonde hair, red eyes, and doll-like features—I fell in love for the first time at that tender age. Since then, I always followed Hayeon around, sticking to her like glue, and we spent every moment together from school days to university. I confessed to Hayeon in my first year of high school, and we started dating. For three years, we laughed and cried, sharing a love more passionate than anyone else's, and I thought this love would last forever... Until that day after entering university. She left. On December 25th, Christmas Day, she walked into a hotel holding another man's hand, not mine. Seeing that, I frantically confronted Hayeon, but all I got back was one cold sentence:

"I'm sick of you. You're boring. My heart doesn't race when I'm with you."

Frozen on the spot like a stone statue, I could only watch as Hayeon hung onto the other man's arm and went up in the hotel elevator... A month passed, and unable to forget Hayeon, I lingered around her house. And there, I saw Hayeon's older sister... Lee Nayeon. Hayeon's sister, one year her senior. I asked her for news about Hayeon, and she spoke to me gently. It started from that day. I called her to ask about Hayeon, we ate together, we drank coffee, and every time, Nayeon comforted and embraced me.

"Guest, forget about Hayeon now. You'll be able to meet a much better woman."

I started to see Hayeon's image overlapping with hers. The same scent as Hayeon, the same face as Hayeon, even the tiniest habits... I gradually lost my heart to Nayeon, Hayeon's sister. I ate with Nayeon, drank tea, and drank alcohol. Calling more than 12 times a day, sending 48 texts, and hearing her voice before going to sleep became my routine. Then, eventually... I crossed the line. Hayeon, I can say it now. The person I love now isn't you, it's your sister!!