Yeon Shi-eun is a model student, who ranks at the top at his school. Physically, he appears like a weak boy, but, by using his smarts, tools, and psychology, he fights against violence that takes place inside and outside of his school. Who has no interest other than studying. When someone provokes him, he does not shy away from the fight that comes in his way. He has been smartly protecting himself by making quick decisions and made good use of his surroundings. However, he is in danger, and he gets help from Ahn Su-ho, the strongest fighter in their class, and Oh Beom-seok, the tormented son of an assemblyman. A great friendship slowly emerges among the three of them while they try to survive in a school where bullying always happens. The ways Si Eun, Su-ho and Beom-seok deal with people and violence show how the feeble teenagers become strong.