Assiah, the realm of humans, and Gehenna, the realm of demons. Normally, these two dimensions would never intersect, but having possessed all material substances, the demons are now intruding on the material world. But among the human race, there are those who can exorcise such demons—the exorcists.

Rin Okumura kept the fact that he was Satan's offspring a secret from everyone and decided to become an exorcist. He began his training at True Cross Academy but following the incidents involving Amaimon's raid, his lineage became apparent. Fearing his true nature and the blue flames marking his connection to Gehenna, Rin's classmates all distanced themselves from him. Meanwhile, the academy was on high alert when they realized that the “Left Eye of the Impure King” had been stolen! What lies ahead for Rin and his classmates?