Oogami spends his day laboring as a detective, yet when the sun sets, he shifts gears and transforms into an exorcist. Alongside Kazari, his spectral companion, Oogami tackles complex cases and tracks down malevolent spirits. However, one ominous day, he receives a horrifying parcel from an unidentified sender, the only clue being the distant village name written on the package: Shirasunamura.