Escaping from Bedlam after three years, Marlott embarks on a quest for revenge against Hervey, as the murder of an archdeacon shocks London.
Suspecting that the clergy killings are linked to Hervey, Marlott takes refuge under an alias in the slums and finds work collecting plague corpses.
Public outrage over the clergy murders mounts as Marlott grows closer to widowed seamstress Esther and interrogates his former nemesis, Billy Oates.
Marlott suspects his allies are in danger after an encounter with mysterious aristocrat Frederick Dipple. Spence reveals the truth about the plague.
Boz confirms that Hervey is still alive, leading Marlott into danger at a supposedly deserted tower owned by Dipple and used to store blocks of ice.
Captured and chained, Marlott must free himself and rescue Esther from Hervey, while rival law enforcement factions unite to apprehend Dipple.
War veteran and police officer John Marlott busts up a smuggling operation on the Thames but makes a grisly discovery that opens a new investigation.
Marlott and Nightingale pursue clues among London's body snatchers and become embroiled in the raging political debate between science and religion.
Making the acquaintance of writer Mary Shelley, Marlott looks into the possibility that the killer he seeks was inspired by her novel "Frankenstein."
Marlott learns more about galvanism and, against the wishes of a smitten Nightingale, uses Flora as bait in an operation to nab a gang of killers.
Boz publishes his newspaper story about the "Frankenstein Murders," angering Peel and sparking public outrage on the eve of the Anatomy Act's passage.
As clues lead Marlott toward his prime suspect, he urges Mary Shelley to go public with what she knows, but she refuses and leaves the country.