Priestly pours generous measures of Dickens and Doyle (Sir Arthur Conan, that is) into this melodramatic murder mystery, set amid the vividly rendered stews of 18th-century London. A shadowy killer stalks the city’s rooftops, each of his arrow-shot victims found with an ominous calling card. Young printer’s son Tom Marlowe becomes involved in the hunt after a lowlife friend, Will, is found strangled; enlisting the aid of canny, well-traveled Dr. Josiah Harker and other adult allies, he is led to crime scenes, taught to sift for clues, and survives several narrow squeaks. The killer turns out to be a tattooed, English-speaking Mohawk with an astonishing head for heights and an otherwise peaceable nature who is exacting vengeance on a gang of thieves responsible for the massacre of his village. Despite the Noble Savage bit, and the fact that Tom’s role in the tale is largely a passive one as his associates do most of the fighting and deduction, fans of Pullman’s Victorian tales may enjoy the similar level of violence and almost tangibly miasmic setting. (Fiction. 11-13)