When a young, beautiful artistocrat is savagely sacrificed in a cemetery on All Hallow's Eve, it shocks the residents of Victorian London. Who would kill a woman like her? And why was she slain in such a cruel way? Another death, that of a young widower and part-time reporter for The Daily Telegraph, occurs on the same day, but to much less fanfare. Only Gemma Tate, the deceased man's twin sister, is left to mourn her brother Victor. Gemma has no connection to the dead woman until the police give her Victor's notebook, in which the journalist had frantically recorded notes about her odd death. His scribbles make little sense, but Gemma is convinced her brother saw something in the cemetery that night. Something that got him killed.

Sebastian Bell has been a police officer for 15 years. A good one, too, until the murder of his wife and unborn child devastated him completely. Now, he's barely going through the motions, preferring to lose himself in a haze of alcohol and opium than face the emptiness of his life. When Gemma seeks him out, begging him to help her find answers to her brother's death, he sees a chance to redeem himself. Victor's notebook doesn't offer much in the way of clues, but it's the only lead Sebastian's got. Although he doesn't want a sidekick, he can't shake off Gemma, who insists on helping with the investigation. 

As Gemma and Sebastian investigate both murders, they find themselves combing London's seedy underbelly as well as its polished drawing rooms for the truth behind the deaths. The closer they get, the more dangerous their pursuit becomes. Can they solve the case? Or will theirs be the next bodies rotting at the city mortuary?