A love story between Jae-hoon, who couldn't let go of his ex-girlfriend, and Seon-young, who is splitting up with her boyfriend. The couple got trouble and were hurt by love.

黑帮头目都锡（郑俊浩 饰）在这一集中进入大学学习，并即将毕业，围绕着都锡在帮中的地位问题，帮众们的意见仍然不统一。而即将毕业的都锡选择进入高中当伦理老师来完成实习，得力干将成滔（郑雄仁 饰）与椰子头（郑云泽 饰）仍然不离左右，成滔在大学期间代替都锡上课并身陷情网，椰子头则一如既往好心办坏事。都锡的授课生涯充满了意外，班上学生之中居然有同样补习文化的帮中大佬，而这所学校，在校董和急功近利的教师操纵下，充满了不公和势利。都锡为了保护大佬不受学校混混的欺负竭尽全力，同时又花心思释放被学业桎梏的学生们，黑帮教师的困难，谁人知晓？

When a young gang leader seems to be just a bit too stupid to effectively carry out his daily tasks, his superiors order him to go back to school for his high school diploma. Posing as a 19-year-old, he soon learns that the school is even more corrupt and vicious. Wrath is unleashed.

When an old collaborator gets severely injured, a veteran policeman tries to figure out the way to bring to justice the ultimately suspected aggressor, a spoiled young executive, heir to a mega corporation, who believes he is above the law.

A high-school teacher in 1983 and a detective in 2015 join forces through their dreams to change the perilous fate of the woman they both love—30 years apart.