Legendary Fighter: Sang-gu, a notorious teenage street fighter, gets tired of fighting when he realizes there’s no match for him anymore. However, one day, his best friend Moon-je gets beaten up by Min-gook, the champion of mixed martial arts tournament in his school. Outraged by what happened, he decides to transfer to Min-gook’s school for revenge and enters the tournament. As he beats other opponents one by one, he gets closer to the big shot of the school, Min-gook.