Do You Know Taekwondo?

"Do-Hyeon (Im Ji-Kyu) is a struggling action actor. He's almost 30-years-old and his girlfriend dumps him because of his immaturity. One day, Do-Hyeon is offered a taekwondo teaching position at his alma mater school. The school has him confused with another person with the same name who was on the taekwondo team years back. Do-Hyeon decides to take the teaching position."