A middle-aged gangster finds himself body-swapped into the body of a bullied teen. Now inhabited by a tough-as-nails gangster, the teen starts to fight back against the power structure at his school and change his miserable existence.

Kim Deuk-Pal (Lee Seo-Jin) is a 47 year old gangster and he is the #2 guy in his gang. He doesn't have an educational background due to his poor parents, but he has a dream of attending a university. He has been studying to achieve his dream, but it's not easy. One day, Kim Deuk-Pal sees a young man Song Yi-Heon (Yoon Chan-Young) about to kill himself. At that time, Kim Deuk-Pal's spirit possesses the body of the suicidal 19 year old high school student. Kim Deuk-Pal soon learns that Song Yi-Heon is a victim of bullying, which has caused him to want to take his own life. Now, Kim Deuk-Pal in the body of Song Yi-Heon, takes on the bullies to punish them and becomes friends with classmate Choi Se-Kyung (Bong Jae-Hyun). Choi Se-Kyung is a model student who appears to be in a perfect situation, but he suffers from domestic violence at home by his father.—AsianWiki