In a futuristic era overrun by gangs, a tournament of super-powered baseball takes place to determine which gang shall rule over all.

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.—MAL Rewrite

Two kids - Haru and Taiga - join forces with Shun, the leader of the Minato Tribe and Neo Tokyo's best Extreme Baseball player. Together they'll play XB against a mysterious man taking control of all the tribes. Can they defeat him before it's too late?—Crunchyroll