1892: James Norbury, a shy would-be poet newly down from Oxford, finds lodging with a charming young aristocrat. Through this new friendship, he is introduced to the drawing-rooms of high society and finds love in an unexpected quarter. Then, suddenly, he vanishes without a trace. Alarmed, his sister, Charlotte, sets out from their crumbling country estate determined to find him. Within the sinister, labyrinthine London that greets her, she uncovers a hidden, supernatural city populated by unforgettable characters: a female rope walker turned vigilante, a street urchin with a deadly secret, and the chilling "Doctor Knife." But the answer to her brother's disappearance ultimately lies within the doors of the exclusive, secretive Aegolius Club, whose predatory members include the most ambitious, and most bloodthirsty, men in England.