In the middle of peaceful days as two top leaders, tender-hearted Jin-man and his friend Min-soo, though both martial arts school legends, felt a new thrill after a mysterious schoolgirl, Soo-jeong, visits their boxing club. Meanwhile, unidentified Japanese high school students begin to raise suspicions in Seoul. The former Japanese yakuza's son, Miura, and the hidden daughter of the Japanese prime minister and center of the nation's far-right forces, Miyo, stirs up a fight between Korea and Japan to determine who is the strongest. Korea vs. Japan! May the last baddest guy survive!

Han-cheol, along with his gang, Geon-mo and Min-ho, tries to be the best in second grade. One by one, they beat out the talented second year students as if beating dojo masters. Han-cheol learns about a master, Jin-man, through a video. Without any idea what is going on, Min-su, wanting to practice finds a boxing ring where Jin-man also practices, and so begins to sleep with the two enemies. However, they need each other so they avoid their uncomfortable jealousies.