Yu is a seemingly apathetic boy with extraordinary boxing talent. When the legendary boxing trainer K encounters him, he recognizes Yu's potential and introduces him to the world of boxing. As Yu begins his journey toward the top of the sport, he faces formidable opponents, each with their own abilities, determination, and reasons for fighting. Through these encounters, Yu's overwhelming talent challenges the boundaries of natural ability and hard work, revealing the different meanings of strength, ambition, and the human spirit.