In 1928 A.D., New York, U.S.A. enjoyed economic prosperity following the Great War. However, this affluence also amplified the presence of the demonic Sinners, an ominous force countered by the Magdalene Order. Rosette Christopher and her assistant, Chrono, are exorcists in this organization, despite their apparent nonconformity. Together, they embark on a search for Rosette's brother, Joshua. Only time will reveal their relationships, secrets, and fates.