"Exorcism" is the art of sending yokai who have somehow wandered into the living world back into the underworld, where they belong. One day Hanae Ashiya, a high school student who's been haunted by a yokai, happens to find the contact information of an exorcist called the "Mononokean" and pays him a visit. The exorcist he meets is a morose-looking young man, Haruitsuki Abeno, and for various reasons Ashiya ends up working for the Mononokean... And so the story of the exorcist duo Ashiya and Abeno, and the yokai they meet in their adventures.