This is a fan translation they have an official translation.

Kim Deukpal,a gangster who lacks an education background, and desires to to complete college, dies in a traffic accident while trying to save a boy, Song I-heon.
"I hope that boy survived."When he wakes up, he finds himself in Song I-heon's body. Deukpal discovers that the real I-heon was being bullied and was outed, which is why he tried to kill himself. Deukpal decides to take revenge for him and attends I-heon's high school.