The day before the ceremony marking the completion of the Yajima Stadium, Nils Nielsen invites Sei Iori, Meijin Kawaguchi, and others to an exhibition battle using the new large-scale battle system he has designed. Now that they are all reunited, Sei attempts to show off the Build Strike Cosmos that he has upgraded for the exhibition, but then he notices something missing... Meanwhile, somebody takes control of the stadium's systems, sealing Sei and the others inside. Before them appears a mysterious group, which has come to challenge them to Gunpla Battle. (Source: Sunrise)

In 19th century Paris, Claude Claudel and his grandfather Oscar run a metalworking shop tucked away in the Galerie du Roy shopping arcade. Back home from his recent travels, Oscar appears with a young Japanese girl—Yune—by his side. Although he is initially against it, Claude comes to accept Oscar's announcement that Yune will live and work with them going forward. Bewildered by Yune's foreign customs, Claude must balance looking after her and managing the shop. But over time, as she settles into her new role as a live-in maid, Claude slowly shows interest in learning to understand Yune and the vastly different world she comes from.

The fierce confrontation among the Kanto high schools reaches new heights with the awakening of dragons in the Kyousho and Seito Academy's leaders, Moutoku Sousou and Gentoku Ryuubi. However, the power balance between these two institutions and their main opponent, Nanyo Academy, is jeopardized when Shimei Ryomou seizes a mysterious dragon orb in China. It is said that the orb grants its strength to a dragon wielder, and Shimei hopes to save Nanyo Academy's leader Hakufu Sonsaku from the adverse effects of her unstable gift. Meanwhile, Moutoku's powers completely consume him, and he loses control over his own body to the Demon King's soul, whose unlimited ambitions endanger the stability of the region and the safety of his allies. In the face of growing tensions to claim the dragon orb, Hakufu and Gentoku will have to put aside their differences and work together to thwart Moutoku's demonic plans.