Korean drama《Gangster I became a high school student》episode plot

The Korean drama - Gangster I became a high school student - is a remake of the novel of the same name. The story tells the story of Kim Deok-pal, a gangster who has never received formal education but dreams of going to school. He gets into a car accident while trying to save Song Yi-heon, a boy who committed suicide due to school violence., when he woke up, he found that he was possessed by the boy's body.