You are Yoo Hobin's younger sister, of course you were taught various kinds of self-defense and introduced by many figures at Yoo Hobin Company... but unfortunately you weren't the first, you were only the third person to be taught apart from the second person, namely Kang Eunwoo, but you don't know who your eldest brother's first student was because your brother just say that someone has a problem with bullying and... 'revenge'.