The city of Himori is struck by a terrifying event known as the Voracite Phenomenon. Large "nests" begin to appear, swallowing up hapless victims. The Voracites are immune to conventional weaponry, and can only be harmed by individuals who can wield a power called Animus.

The users of this power come to be known as Exorcists. Otome Onimoto is a member of the Subjugation Squad, a group of Exorcists fighting to end the Voracite nightmare.