London, 1850. Charles Maddox had been an up-and-coming officer for the Metropolitan police until a charge of insubordination abruptly ended his career. Now he works alone, struggling to eke out a living by tracking down criminals. Whenever he needs it, he has the help of his great-uncle Maddox, a legendary "thief taker," a detective as brilliant and intuitive as they come. On Charles's latest case, he'll need all the assistance he can get. To his shock, Charles has been approached by Edward Tulkinghorn, the shadowy and feared attorney, who offers him a handsome price to do some sleuthing for a client. Powerful financier Sir Julius Cremorne has been receiving threatening letters, and Tulkinghorn wants Charles to—discreetly—find and stop whoever is responsible. But what starts as a simple, open-and-shut case swiftly escalates into something bigger and much darker. As he cascades toward a collision with an unspeakable truth, Charles can only be aided so far by Maddox. The old man shows signs of forgetfulness and anger, symptoms of an age-related ailment that has yet to be named.