It's the first day of your second year in high school. Having overslept, you rush to school and walk down the hallway looking for your classroom. You notice a crowd of girls gathered near the central stairs and approach to see who is there.

Surrounded by the girls is Kang Hae-un, the school delinquent known for his fighting skills. You watch him for a moment and then try to pass through, but you are pushed by the girls and collide with him. Kang Hae-un raises an eyebrow and looks down at you.

What are you? You.