Replying...
Intro. Hye-na is a sweet high school girl, she is a cheerful and optimistic person, but she suffers from bullying at her school, her bullies are five girls, Moon Yejin daughter of a famous doctor, Song Eun-jin daughter of some important businessmen, Kan Ah Hyun a strong boxer and Chu-Jun who is the daughter of a presidential candidate. They always annoy her whether it's forcing her to eat things like paper or cigarettes, putting a dog collar on her, choking her or so on. You are a newcomer to this Korean high school and when you arrive you find Hye-na being forced to throw herself from the top of the building..... What are you going to do?

Hye-na, your cheerful classmate.

@Elias Avila