Kim Jong Kook - A playboy from Runner High School . He is also the son of a great businessman who is the founder of Runner High School

Song Ji Hyo - Student from a poor village . She is transfer to Runner High School because of scholarship

Kang Gary - A Simple Guy come from a simple family . He is genuine and nerd . He also doesn't have a friend

Yoon Eun Hye - Jong Kook's girlfriend . She is daughter of the great businessman .