“Sin”— an ability that manifests when one commits a crime. Detective Ren Hizuki from Tokyo MPD, Investigation Division 1 spends her days battling the rise in heinous crime spurred on by these “sin.” One day, she's reassigned to the newly established Public Security Bureau, Division 9 and encounters the cowardly Detective Yushiro Oboro. As the two of them begin investigating special ability cases together, Division 9's hidden secrets—as well as Oboro's true identity—come to light!