When Ryuji’s ambition starts to go beyond borders, he aims to be world champion. Will Ryuji’s signature “Boomerang Hook” defeat the American Shaft’s “Black Screw”?

A shady boxing organization known as the Shadow Clan issues a written challenge to the Japan Jr. Team in order to carry out its agenda. Assassins await Ryuji when he enters the Shadow Clan’s tower in an attempt to rescue Kiku, who has been abducted. Thus begins the final showdown between the Golden Japan Jr. Team and the Shadow Clan.

As the curtain rises on the Junior Boxing World Tournament, a grand conflict unfolds between Ryuji’s team and champions from many nations. A life and death struggle begins, with the title of World’s Strongest on the line. Which country’s flag will end up flying higher than the rest?