In order to fulfill their dead father's wish, the siblings, Takane Kiku and Takane Ryuji aims for the champion title of the boxing arena. The sister, Kiku, will act as the trainer while her brother, Ryuji, will concentrate on the role of the boxer and learn the Boomerang. His battle with many rivals has led to the growth and maturity of Ryuji. The junior high boxing tournament has began and Ryuji will be fighting with his arch-rival, Kenzaki Jun. The battle begins.

[Source: Anime News Network]

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 Juliano, the Italian Junior Champion, just in case...

[Source: Anime News Network]

After defeating Black Shaft's makeshift Team America, the Golden Japan Jr. team returns to training for the World Tournament that will be held in Tokyo. But during training the Shadow Clan, which uses boxing as an assassination technique, kidnaps Kiku in order to lure Ryuji and the others into a fight to see who's truly the better representatives of Japan's junior boxers.

[Source: Anime News Network]

After defeating Black Shaft's makeshift Team USA and proving their worth to the Shadow Clan, Team Golden Japan Jr. will finally enter the World Jr. Boxing Tournament. In order to fulfill their goal of a perfect victory they'll have to take on teams from countries like Mexico, Italy, France, Germany, and the mysterious and godlike Team Greece.

[Source: Anime News Network]