In 2046, a groundbreaking 80‑percent shock‑absorbing composite cardboard was invented, swiftly reshaping global trade. This reinforced material soon became the arena for a kids" pastime known as "LBX" (Little Battler eXperience).
Four years later, a youngster named Yamano Ban—who enjoys LBX yet owns no mecha of his own—receives a crate containing the AX‑004 model from an enigmatic woman. She informs him that he now carries humanity"s hopes and fears in his hands, as if the weight of the world rests upon him.