Kang Bok-Soo was wrongly accused of violence in high school and expelled. Son Soo-Jung and Oh Se-Ho caused this. Now an adult, Kang Bok-life Soo's hasn't been easy. He returns as a student to wreak revenge on Son Soo-Jung and Oh Se-Ho. Kang Bok-Soo gets embroiled in unexpected cases as the school changes.