The story centers around the life of a young boxer named Takane Ryuji and his sister Kiku, who is his coach. Ryuji and his sister inherited their father`s talent for boxing. Ryuji nasledovad his powers and methods, while Kiku picked up his talent for analysis and strategy.In the past, their father was a famous boxer. Ryuji and Kiku left home to train and become known, in order to help their single mother. On the way to glory, they must defeat the strongest contenders in the world.