The pain of losing a loved one can be so intense that one might wish to resurrect them—a vulnerability exploited by the enigmatic Millennium Earl. He creates mechanical weapons called "Akuma" by using the souls of the dead that are called back. Once a soul is placed inside an Akuma, it is trapped forever, and the only way to save it is to exorcise it from its vessel using the Anti-Akuma weapon, "Innocence." After spending three years as the disciple of General Cross, Allen Walker is sent to the Black Order—an organization comprised of those willing to fight Akuma and the Millennium Earl—to become an official Exorcist. With an arm serving as his Innocence and a cursed eye that can see the suffering souls within an Akuma, it is up to Allen and his fellow Exorcists to stop the Millennium Earl's ultimate plot: one that can lead to the destruction of the world.