It tells the story of high school student Song Yi Heon (played by Yoon Chan Young) who was tortured by school violence and tried to commit suicide by jumping off a bridge. The second boss of the underworld, Kim Deok Pal (played by Lee Seo Jin), sacrificed his life to save him but accidentally his soul passed through him!De Ba, who originally had a college dream, mistakenly returned to school as Yi Xian. Not only did he severely teach the perpetrators, he also established new friendships with classmates who suffered domestic violence.At this time, Cui Sejing (played by Bong Jaehyun) noticed his changes, and even suspected that the “Yiheon” in front of him was not the same person.