The middle school bully world in Seoul is divided into Gangnam and Gangbuk, where Ji Hyeon-soo from Namchun is the head of Gangnam, and Han Jeong-pil is the head of Gangbuk. Known as 'the two kings', their fighting skills cannot be matched by other gangsters from other middle schools, and no one dares to challenge them. Then one day, a goblin comes out of nowhere and the kings are beat. Since then, he becomes the best legendary fighter in the gangster world. Time passes and all the middle schoolers, including the top two, move on to high school and they take over all the schools with their excellent fighting skills, making their way to the top.

Na Kyung-soo, a diver, is angered to learn that the Coast Guard is assigning responsibility for the death of a fellow diver during the Sewol ferry disaster recovery to Ryu Chang-dae, the representative of civilian divers, and charging him with manslaughter.