Teen exorcist Allen Walker is given his first assignment, and his perilous mission takes him to southern Italy, where an Innocence has been located. Along with fellow exorcist Kanda, and Tom, a "finder"--one of a support group for exorcists--Allen must vanquish the akuma that covets the Innocence.
Allen and his fellow Exorcist, the formidable and misanthropic Yu Kanda, discover the latter’s background—including his true nature and purpose—in visions that flash back to his childhood. Yu’s memories of this time have long been suppressed, and it seems for good reason. They not only involve Yu but another child named Alma, and expose how desperate certain factions within the Black Order were to counter the threat posed by the akuma and their master, the Millennium Earl!