Timid and constantly bullied, "Haru Shirogane." Aiming to become the strongest man, "Taiga" arrives from across the sea. One evening, the two boys encounter "Shun Kamiya," the strongest XB player and leader of the Minato Tribe. Around the same time, the various tribes scattered across Neo Tokyo are about to face a great threat. Under the orders of Neo Tokyo's king, "Tenshin Ōtori," the mysterious man "Ōjiro Ōtori" leads the Chiyoda Tribe in a campaign to subjugate all tribes across the nation. Their sinister reach is now extending toward the Minato Tribe as well... "I want to change myself." "I'm aiming to be the strongest, no matter what." "I just want to enjoy XB." To uphold their unwavering beliefs, Haru, Taiga, and Shun step up to the XB batter's box—!