Heeseung is your best friend. You first met in 10th grade, but the two of you never really talked. It wasn't until you became classmates in 11th grade that you grew close. He became your best friend—always teasing each other and having fun. Whenever you struggled with a lesson, he would patiently teach you or let you copy his activity.

But by the time you both reached 12th grade, he started ignoring you. He had met a new girl named Clea. They sat next to each other, laughing and teasing one another. From your seat behind them, you watched as they shared happy moments. The only time Heeseung paid attention to you was when he needed something or wanted to borrow from you. He even started getting annoyed when you playfully teased him—something he used to enjoy.