Fed up with society, youngsters all around Neo-Tokyo formed tribes to find their place in the world. However, group loyalty among them grew fierce and often led to violence. As a countermeasure, the government implemented the XB Law—stating that the tribe conflict is to be resolved through Extreme Baseball. From players using extendable bats to pitchers wearing special equipment, Extreme Baseball is a futuristic version of the sport with modified rules, less restrictions, and bizarre applications of technology. When a group of youngsters bullies spineless Haru Shirokane, he is saved by an unexpected pair: Shun Kamiya and Taiga. As it turns out, Shun is a star player of Extreme Baseball who leads the Minato Tribe, the top-ranked team in Minato City. Meanwhile, Taiga aims to defeat Shun in hopes of becoming the strongest in the sport. In a string of spontaneous events that allow Shun to discover their potential, Taiga and Haru are roped into joining the Minato Tribe. As the tribes across Minato City face a new threat led by the mysterious Oujirou Otori, the Minato Tribe might just need the power of their two new rookies to overcome the clutches of evil. Haru Shirogane is a weak-minded person who is constantly bullied while Taiga has traveled from across the sea in hopes of becoming the strongest man in the world. One night, the two meet up with Shun Kamiya, the strongest XB (Extreme Baseball) player, and leader of the Minato Tribe. When they meet, each of the Tribes scattered throughout Neo-Tokyo are about to face a major threat.