A series to commemorate the 10th anniversary of the "Gundam Build" franchise. A new Internet service has been born in the world of Gunpla. Within the Metaverse realm, the user can control their own avatar, interact with other users, play Gunpla Battle, and purchase actual Gunpla. Rio Hojo is a boy who has dived into this new world. Studying Gunpla building techniques in the real world with Seria Urutuski, and absorbing Gunpla Battle know-how from Mask Lady in the Metaverse world, he has been honing his skills day by day. After completing his own original Gunpla, the Lah Gundam, Rio happens to encounter some past champions of Gunpla Battle in the Metaverse realm.

After the end of the Hokuriku front, a new land for the Japanese people was created, governed by the New Japan Cooperation Organization. However, this did not dramatically improve the situation in Japan. The effective control of the various powers in the country continued, and the oppression of the Japanese people, though lessened, continued. The same is true of the isolated islands in the South Sea. The Oceania Army, which is in effective control of the island, and the resistance organization "Hinukan" that resists them. Then the North American forces attacks, aiming to take over the isolated island--.

Famous for his military service in the 39th Asian War, the legendary Swiss robot Montblanc is violently murdered. Humans and robots around the world mourn for the beloved celebrity. Montblanc's popularity only grew in the years following the war, thanks to his dedication to nature conservation and his loving personality. Once a fellow war veteran, robotic Europol detective Gesicht is sent to investigate Montblanc's tragic demise. In his pursuit, Gesicht uncovers evidence of a mysterious entity known only as "Pluto." He also learns of a conspiratorial plot to dismantle the eight specialized robots from around the world who participated in the war. Racing against time to save those who still remain, Gesicht grapples with his memory, morality, and a world full of hate, desperately attempting to defend the fragile coexistence of man and machine.

After their world was saved by Gridman and Akane Shinjo returned to the real world, Yūta, Rikka, and Utsumi return to their normal lives, though Yūta still has to adjust to losing two months of his memories due to being possessed by Gridman during that time. Rikka and Utsumi work on writing a script for a play their class will perform in the upcoming school festival based on their experiences with Gridman, while Yūta tries to work up the courage to confess his feelings to Rikka. However, their life is disrupted when a kaiju suddenly attacks the city. Yūta voluntarily fuses with Gridman again to fight the kaiju, and is assisted by the return of the Neon Genesis Junior High Students, who now count a newly revived Gauma who commands DynaRex as their newest member. Gridman and the NGJHS defeat the kaiju, and explain that some unknown phenomenon is causing different universes to overlap in a potential Big Crunch.