Sergeant Nathaniel Brannick is trapped in Victorian London during a period of disease, crime, and insatiable vices. One night, Brannick returns from work to find an eerie messenger in his flat who warns him of dark things to come. 

When his next case involves a victim who suffered from consumption, he uncovers clues that lead him to believe the messenger's warning. Despite his incredulity, he can’t help but wonder if the practical man he once was has been altered by an investigation encompassed in the paranormal. That is, until he meets the witch hunters, and everything takes a turn for the worse.