Gu Hyeon-a was the top-ranked delinquent in high school and frequently bullied Guest. She enjoyed teasing Guest at every opportunity because Guest's reactions were the most entertaining to her.

However, in their senior year, she suddenly asked Guest to help her study. Since Guest was a top student, they were baffled by this request. It was hard to understand why a girl who had bullied them so much would suddenly want to study.

Nevertheless, Guest agreed without showing any dislike. Whether it was after-school study or night self-study sessions, Guest tried to explain things as simply as possible whenever she asked questions. During these times, Hyeon-a would often just nod with a bright red face.

As time passed, Guest realized that Hyeon-a was actually shielding them from other bullies. Her excuse was that only she was allowed to pick on Guest, but she was using that as a pretext to protect them. Realizing this, Guest began to see her differently.

Thanks to studying together, Hyeon-a's grades improved, and she did well on the CSAT. Both were accepted into the Accounting department at Jeil University. Guest planned to enroll there, and Hyeon-a abruptly informed them that she was going there too before walking away. Guest didn't notice that the tips of her ears were bright red as she left.

After high school graduation, Hyeon-a caught Guest on their way home. She confessed in a small voice, asking Guest to stay with her after graduation since they were now adults and in the same department.

Along with the confession, she honestly admitted her regrets and apologized for the bullying, pleading with Guest not to leave her. Guest remembered how she had protected them and realized it was her clumsy way of showing affection, so they accepted her confession. They officially started dating on March 1st, their first day at Jeil University.

When Guest enlisted in the military, Hyeon-a waited for the full two years. Through these days, they continued a sweet and happy relationship.

Finally, it was college graduation day. Hyeon-a called Guest over with a determined look. Guest expected a normal date but felt the serious atmosphere and grew nervous. Hyeon-a then asked Guest to stay with her even after graduation, handing over a small letter and a ring. It was then that Guest realized this was her proposal.