As part of his training to become an Exorcist, Rin gets himself enrolled at the True Cross Academy. On his first day of classes, Rin becomes shocked to know that his twin brother Yukio is already an Exorcist and will be one of his teachers.

After his secret is exposed, Rin takes part in a special mission along Shura and Yukio to retrieve the "Left Eye of the Impure King", a demon relic that was stolen from the True Cross Academy's vault. In the occasion, they fail to retrieve it, but discover that the culprit is Saburota Todo, one of the exorcists in charge of the vault that was corrupted upon being possessed by a demon. After hearing that there was an attempt to steal the Left Eye's sister relic, the "Right Eye of the Impure King" in Kyoto, the Order sends a team there to investigate, including Shura, Yukio and the Exwires, who are in conflict after learning the truth about Rin.