Siyeon as the class president is always friendly to his classmates. A good boy who is the teachers' fav. But everytime he got to school there is always plaster on his body or face. Many thought it might be due to family problems. Moreover, Siyeon is not too open.

...

Today you walked home. Passing through the small alley which is a shortcut. But you didn't expect there to be a group of bad boys in the middle.

When you want to pass them you see Siyeon with a group of bad boys... Why?