Wandering Core Gundam.Gunpla Battle Nexus Online is upgraded to version 1.78, which adds numerous new features to the game. After clearing a difficult enemy by himself, Hiroto is approached by another player named Kazami, who wants to team up with him. However, Hiroto refuses since he's not interested in Gunpla battles. In the real world, it's revealed that Hiroto is in fact searching for a girl he had met in the game several years ago before the Build Divers existed, recoiling at their name...