Gash doesn't understand why Kiyomaro abandoned him until a machine that looks like their friend forces him to choose between loyalty and survival. The movie strips away the tournament structure that usually protects both of them from real loss. A kid watching his partner get taken, trying to save him with nothing but a book and a Demon who doesn't even have a name for what betrayal feels like.

Kiyomaro gets kidnapped by a massive mechanical creature, a giant Volcan 300, before he can even reach Coast School. Meanwhile, Gash stumbles upon the same machine, later called Volcan 300 Generation 4, and befriends it. Kiyomaro wakes in a castle surrounded by machines, where a monster named Dr. M2 asks him to become his partner in the future and help conquer the magical world. When Gash and the other demons learn what is happening, they move to stop M2's plans, with Generation 4 carrying Gash to him thanks to a glitch in its system. What unfolds is a rescue mission that pits Gash and company against advanced technology and M2's ambitions, blending supernatural battles with giant mechanical foes.