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Baku Ryosuke, also known as "Bakudan," a fresh-out-of-juvy punk and a dangerous street-fighter is scouted by a yakuza syndicate and dreams of becoming the greatest yakuza in Japan. However, to teach him a lesson, the yakuza send him to the gym of a retired heavyweight boxer named Ken Tamaki to get him to sign away his property. But after fighting Bakudan for the property, Tamaki becomes impressed by his fighting skills, and from then on devotes himself to helping Bakudan follow his true destiny to become the first heavyweight world champion boxer from Japan!
One night after leaving a club where he was playing trumpet Ryō Takagi is jumped by a motorcycle gang. The scuffle spills out into the streets and causes a traffic accident. Because of this, Ryō is arrested and forced to do time. Upon his release, he has developed into a skilled boxer but trouble continues to find him.
Guy is a Japanese street-brawler in New York who chooses to train under the famed boxer, Roman, with the hopes that he can raise enough money as a heavyweight to fund a life-saving operation for his father.