Losing a loved one is so painful that one may sometimes wish to be able to resurrect them-a weakness that the enigmatic Millennium Earl exploits. To make his mechanical weapons known as "Akuma," he uses the souls of the dead that are called back. Once a soul is placed in an Akuma, it is trapped forever, and the only way to save them is to exorcise them from their 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 as his Innocence and a cursed eye that can see the suffering souls within an Akuma, it's 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.