After the collapse of the bubble economy, people who purchased cheap second-hand properties and moved into the remains of a subdivision—abandoned midway during development—began to disappear without a trace. The subdivision remnants had literally turned into a ghost town, with a strong miasma enveloping the entire area. As the case was beyond the capabilities of the police, the agency Onmyōryō, which manages and subjugates non-human entities, dispatched the young onmyōji Haruhisa Tatsumi and his partner, the demon Anneliese, to investigate the incident. Upon arriving at the site, they immediately encountered a bizarre phenomenon shrouded in intense malice, realizing that this mission would not be straightforward. An extraordinarily powerful darkness lurked behind the incident. Armed with a mystical katana that can cut through unseen threats, Haruhisa steps into the hidden realm between the present world and the eternal world—the Reverse World—together with Anneliese.