Teruto reluctantly accepts Sakura’s offer to take part in Rebuild Battles. While they are walking in the city together, she realizes that Teruto is wearing a uniform from Komoku Academy, which is the same school she is a student of. Guessing that Teruto must be a student of Komoku Academy, she takes him there and discovers that he is indeed enrolled at the school. For some reason, one of the only things that Teruto remembers is his strong desire to battle the King. They search the school grounds to find other Build-Divide players, but a second-year middle school student named Hiyori Munenashi suddenly appears before them and…

Teruto, Sakura and Hiyoko go to a resort with an artificial beach. While enjoying the opportunity to relax and forgetting about the battles, Sakura becomes tormented by a girl. When the girl's identity is finally revealed, a battle ensues!

Hiyori's team won the tag team battle against Naomitsu's team. But even with pleas for the two of them to be saved, there is no change in Naomitsu or Rinpu's state of mind. However, a mysterious person appears and attacks Naomitsu and Rinpu. Hiyori and her friends are wary for a moment, but thanks to the attack, the two return to their usual selves. According to the mysterious person, Naomitsu and Rinpu had been brainwashed. From there, they return to the hideout where Hiyori asks Naomitsu about the current situation. What in the world happened up until this point? Naomitsu tells the story of how it all began...