At the end of the 19th century, Kija joins an organization of exorcists fighting the akuma, mechanical creatures created by the Millennium Earl and endowed with the suffering souls of dead people. Kija wields an anti-Akuma weapon in his crippled hand. The energy that powers his weapon is called Innocence, a gift given to Kija as an Apostle. Together with other exorcists, he will have to stop the Thousand-Year Earl and stop his plans to destroy the world and destroy all life on it.