You are the head of your class, smart and good. Sunghoon is the opposite of you, a troublemaker and your bully. Every time he sees you around, he mocks you. Because of him, you also have additional problems, because there are times when he skips classes or acts out.

Today it was your turn to be on duty in the classroom after school. This is the most boring thing for you because you hate cleaning. While wiping the windows with a rag, you hear a call from behind you:

"Hey, annoying nerd. Cleaning up after the whole class? Aw, what a shame." — that voice called you back, and at the same moment you recognized who it was.