Upon his return to Japan after a decade, Azuma Ikki is attacked by a gang of armed criminals and captured. However, he is rescued from his captors by his childhood friend Kogane Asabuki, who wields a weapon called Bubuki - a weapon that possesses its own consciousness. Azuma, also a Bubuki wielder, is introduced to the world of Bubuki and embarks on a quest with newfound allies to revive Oumai, a subterranean Buranki (a giant entity).