Fifteen-year-olds Satoyama Katsuki and his best friend Kawakami Kyouta join Mizutani Boxing Gym to get closer to their tomboyish crush, Mizutani Katsuki, whose father owns the establishment. However, Satoyama soon discovers that she is distant from her father. Worse, it turns out that she hates boxing. During a sparring match, everyone, including Mizutani, soon discovers Satoyama's hidden yet unpolished boxing skills. Satoyama soon learns that Mizutani is actually in love with boxing but disdains it because it is a man's sport that she cannot join. Mizutani then takes it upon herself to become Satoyama's trainer and manager to reach the championship belt. Satoyama complies to be closer to his crush. As the story progresses, it is soon revealed that Satoyama has a hidden past and lineage, one that would give him the necessary skill and talent to become a legendary Oriental pro-boxing champion.