Rin and his exorcist classmates are caught in a secret war against the forces of darkness. Raised by Father Fujimoto, a famous exorcist, Rin Okumura never knew his real father. One day a fateful argument with Father Fujimoto forces Rin to face a terrible truth—the blood of the demon lord Satan runs in Rin’s veins! Rin swears to defeat Satan, but doing that means entering the mysterious True Cross Academy and becoming an exorcist himself.

As the world transforms beyond comprehension, the Knights of the True Cross still struggle to save it. But they have paid a heavy price to get Rin and Yukio's team into the labyrinth surrounding Satan's stronghold. While Arthur A. Angel and the others keep up the fight against Iblis, the infiltration teams push toward their objectives.