Having suffered ruthless bullying for the better part of his life, 17-year-old Yu has become emotionally numb and dissociated from reality, no longer able to act like a normal human being. Although he possesses the exceptional talent to dodge punches, Yu prefers to let his perpetrators beat him down as he finds no meaning in his survival.

Things begin to look up when Yu meets an old boxing trainer nicknamed "K." Having raised five champions, K's years of experience and an impressive gut feeling allow him to recognize Yu's near-superhuman fighting charisma immediately. K rushes to take Yu under his wing, despite the latter's apparent lack of interest.

However, after being reminded of a bright memory from the past, Yu has a change of heart and accepts K's offer, hoping to experience the same light once again. Thus, Yu enters a world full of formidable adversaries—righteous and monstrous alike—and for the first time ever, he has no choice but to fight back.