When the police arrest a gang of opium smugglers on the banks of the Thames, Inspector John Marlott makes a shocking discovery in the form of the body of a dead child washed up on the shore. He is ordered by Home Secretary Sir Robert Peel to lead the investigation, however details must remain confidential.

After his discovery on the banks of the Thames, Inspector Marlott visits the house of artist and printmaker William Blake, who is on his deathbed. Later, Marlott confers with Nightingale, a local policeman who has been keeping watch on The Fortune of War, a public house where body snatchers are known to gather. The pair create a plan to capture a person of interest who may be able to aid them with their investigation.

Having escaped the clutches of Billy Oates, Flora throws herself on Marlott's mercy. As the investigation continues, Marlott travels to Kentish Town to interrogate Mary Shelley.

Marlott and Pritty find themselves in the tunnels under Smithfield market, which run from the Fortune of War pub to St Bart's Hospital.

Boz publishes his newspaper article, The Frankenstein Murders, which causes a public outcry and infuriates Peel on the eve of the Anatomy Act.

Inspector Marlott pieces together the links in the chain to connect the supplier of corpses with the his final suspect.