This novel is a mystery/steampunk/dark fantasy story, set in Victorian Liverpool, with a bit of police procedural thrown in for good measure. The hero, Inspector Matthew Langton, is a recent widower haunted by dreams and flashs of confinement and fear involving his dead wife, Sarah. As he plunges himself into his work to battle his grief, investigating the gruesome murder of a faceless man, he finds hints of a sinister group, the Jar Boys, who trap souls at the point of death, and rent out the souls' experiences to jaded, upper-crust addicts.
As he investigates, he comes to realize that his wife's soul is one of the many who have been trapped by the Jar Boys and rented out - causing his wife's soul to become 'tainted' with the experiences of others. As he continues to investigate, murders by the mysterious Doktor Glass (a truly frightening villain) begin to mount, as someone within the police force leaks Inspector Langon's every move. He also begins to realize that the murders are somehow linked to the upcoming triumphal opening of the Transatlantic Span (bridge) connecting Liverpool and New York - and its imminent destruction.
Inspector Langston must juggle the conflicting priorities of rescuing his wife's soul, solving the mounting murders, finding the mysterious Doktor Glass, and saving the Transatlantic Span and Queen Victoria all at the same time. His burden is made heavier with the realization that the souls of the deceased can be placed in a new host body, as one of the antagonists proves. Inspector Langston must struggle with his conscience when given the opportunity to have his beloved Sarah back, in another host.
The story is well-written and engaging without so many characters that you lose the thread of the tale. I'm a long-time science-fiction and fantasy reader who grew up on "Ringworld", "The Moon is a Hard Mistress", and the like, and steampunk is relatively new to me, but if you enjoyed such novels as "The Strange Affair of Spring Heeled Jack" and the Rivers of London series by Ben Aaronovitch (which I cannot recommend too highly), then you will really enjoy this story, as I did.