My Strange Hero contains a sketch of the turbulent life of the main character Kang Bok Su. By showing Kang Bok Su's life from his school days, this drama presents how a good teenage boy has gone bad and how he grows up into a good adult by resolving misunderstandings. Kang Bok Su was a handsome and good-natured high school student. He willingly helped his schoolmates who were in trouble and fought against anything he believed unfair and unreasonable. Naturally, most of his schoolmates liked him. One day, however, he was falsely accused of bullying his classmates and ended up being expelled from school. Even his girlfriend and best friend didn't trust and betrayed him. Now, as a grownup, he plans to go back to the high school and take revenge on those who framed him and made him suffer since his teenage years. However, things start to go wrong. Bok Su gets to be involved in a series of incidents and falls in love in the high school.