Shiemi manages to calm down Rin, who is captured by Arthur Auguste Angel, the current paladin, and taken to the True Cross Order Headquarters in the Vatican along Shura and Mephisto Pheles. Meanwhile, Rin's classmates become astonished when Yukio reveals to them that he and his brother are sons of Satan, but offer their help regardless, and they set for Kyoto looking for the descendant of the swordsmith who forged the Demon-Slaying Blade to have it fixed. Before the Order's upper echelons, Mephisto states that his reason for keeping Rin alive is to have him confront Satan, and just when he is trying to convince them to agree to his plan, an enraged Amaimon breaks in, eager to confront Rin once more.

Rin and his companions manage to flee from Satan who starts destroying the True Cross Academy with his flames. Knowing that Satan still stands beside the Gate because Rin has the power to destroy it, Shura comes up with a plan to distract him to give Rin an opening to do it, while the other students help evacuate the school. Their plan fails when Shiemi intervenes trying to dissuade Yukio with no success, but Rin manages to have his brother regain conscience and expel Satan from his body. However, the gate keeps getting stronger and it will not be long for Gehenna and Assiah to merge into one single realm.