BBK/BRNK

Kazuki Azuma returns to Japan after ten years away, only to be chased down by the Bubuki police. He's saved by a childhood friend, Asabuki Kogane, and her right-hand-shaped Bubuki. He then meets the Bubuki users Nono Hiiragi, Ougi Kinoa, and Taneomi Shizuru. Azuma has never even heard of Bubuki, but after learning that he's the user of the "heart" Bubuki, he makes his way to the Buranki prison in Shinjuku's underground to awaken the sleeping Buranki called Oubu.

Azuma stares in stunned shock at Oubu, now reduced to bones, as Hiiragi, Kogane, and the others successfully hold off Matobai. Hiiragi realizes this is the best chance to awaken Oubu and demands the heart Bubuki from Azuma, but Azuma insists he has no such thing. Believing that the heart Bubuki will react if its owner is in danger, he attacks Azuma with Iwatooshi!

Ten years ago, many Buranki fell to Earth and were destroyed by Banryuu Reoko and her Buranki, Entei. That was the day Reoko and Entei's reign of terror began. In the present, Azuma and his companions flee Shinjuku and meet a woman named Horino, who tells Azuma that his mother was the only person who ever defeated Reoko. She then tells him there's more he should know, and leads him to the "Kazuki library."

Kogane's enraged cry of "I'll gouge out your everything!" rings out as she engages Matobai in battle, but her opponent's attack power overwhelms her. When Azuma tries to help her, Matobai mercilessly fires his Bubuki gun at him, but the heart Bubuki shields him. Azuma tries to use the heart to call Oubu to fight, but it doesn't respond... and Matobai sneers at their confusion as he takes out Entei's heart Bubuki.

The Bubuki battle continues aboard the train that's carrying Oubu toward Treasure Island. A beam fired from Arabashiri's Bubuki ring hits Kinoa, causing her own past to replay in her mind and slow her down. Azuma tries to help, but Kinoa stops him, saying she must settle her own score with Arabashiri. So Azuma agrees to just watch, but Hiiragi can't help wondering what Kinoa's relationship with Arabashiri is. What really happened in their past?

Azuma's companions have won their second Bubuki battle, but the next opponent is one of Reoko's Four Gods who was in disguise as their friend Horino. Hiiragi and the others are shocked to learn that their trusted friend is actually working for their mortal enemy. Kinoa demands to know why she betrayed them, but Zetsubi easily dodges the question; Hiiragi attacks her in rage, but he's no match for the power of Zetsubi's Bubuki. Azuma's suggestion of figuring out what the opponent's Bubuki's power is momentarily calms Hiiragi, but soon enough...