Immediately after Ryuuji Takane won the Champion Carnival, the U.S. Junior Champion Black Shaft appeared, and challenged the best Japan has to offer, just before the World Tournament is about to happen. Now Ryuuji, Takeshi Kawai, Kazuki Shinatora, Ishimatsu Katori, and Superstar Jun Kenzaki have to prove to not only Black Shaft, but the world, that they are truly world-class boxers before the World Tournament starts. But Shaft is not recruiting boxers for his challenge, but instead gets a life-timer criminal from Death Row, the leader of the Great Angels, one of the toughest gangs in America, a mysterious woman, and the "Dark Emperor of the South". Also, Shaft negotiates with Don Giuliano, the Italian Junior Champion, just in case...