Whitechapel, 1888. Five women murdered. A killer the press has named Jack. Scotland Yard is drowning in false leads, public hysteria, and the Queen's increasingly desperate dispatches.
When a stranger steps off the night train from Dover with letters of recommendation from Her Majesty's private secretary, Chief Inspector Abberline finds himself with an unexpected partner: Edward Corwin Raven, consultant on occult crimes, ritual murders, and the kind of cases the official record prefers to forget.
Raven is charming, well-read, and unsettlingly informed. He has theories about the killer that the Yard's senior officers would dismiss as madness, were they not slowly proving correct. He asks questions no one else thinks to ask, and follows them into asylums, forgotten chapels, and the back rooms of Masonic lodges.
But the more Abberline learns about his new consultant, the less he is certain Raven came to London to help. And the closer they draw to the truth of the Whitechapel killings, the harder it becomes to say which of them is investigating whom.