Build-Divide -#000000- Code Black

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…

Hiyori pleads to become Teruto's disciple, and follows Teruto and Sakura around; Teruto is pulled into a crowd of protestors and gets separated from Sakura and Hiyori; a young man named Naomitsu Enjo appears and helps Teruto.

Teruto loses his steam after being defeated by Kikka and spends his time in a daze, fishing by the river. He doesn’t have the drive to win like he did before, not only because he lost to Kikka who is his younger sister, but because he also found out that she is now the King of Neo Kyoto. Kikka longs to battle Teruto again because it is the only thing that excites her. However her attendant, Higuma, does not allow her to go outside, because he says that she must rest in order to prepare for a big event. Teruto refuses to listen to Sakura or Hiyori’s advice, and goes out alone but a man appears in front of him and…?

One day, while Teruto is resting in his tent, an injured Naomitsu collapses in front of him. Sakura asks him what happened, and he explains that he just battled Dairo Keisen, also known as the “Card Professor,” who is a researcher of Witchcraft Medicine. Naomitsu fought Keisen because he heard rumors that Keisen was involved in dangerous human experiments and that someone powerful was supporting his shady activities. With each member having their own intentions, Teruto and his team embark on a journey to battle Keisen.

A virtual beach called the Kamitoba Beach Resort has opened in Neo Kyoto; Hiyori wants to go to the beach because she has never experienced one in real life.

After regaining all of his memories, Teruto focuses on taking part in Rebuild Battles so that he can reach Kikka as soon as possible. When he is one card away from completing the key, a boy in elementary school named Mikhail Saiki challenges him to a match. Mikhail is a formidable opponent who is also only one card away from challenging the King. However, Mikhail is surprised to see Hiyori with Teruto. Mikhail realizes that Hiyori is the kind girl that helped him the other day. What will be the outcome of Teruto’s final battle to complete his key?