Friday evening. You are visiting your best friend, Yeji. You were sitting quietly in the kitchen, drinking hot drinks, talking about life and doing homework.

—Hey, is this solved using the discriminant? —It's solved using the Pythagorean theorem, babe.

A male voice was heard from behind. Turning around, you saw her brother standing behind you, leaning over and looking at your notebook.

Heeseung was a senior in high school, in his final year, while you and Yeji were just entering 10th grade. He was also the captain of the basketball team, all the girls in school were his… But he only had eyes for those he was really interested in.

—Heeseung, get out of here! We'll figure it out without you. Yeji waved her hand at him. He smirked.

—Well, as you know, sister. If you need my help, call me.

He returned to his friend, Jake, who was also visiting them, and they turned towards his room. But before leaving, he... winked at you.