From London's vilest slums to its grandest palaces, Wild Boy and Clarissa hunt a murderous prisoner in hope of proving themselves to a skeptical society.

London, 1842. Wild Boy, master detective and former freak-show performer, and Clarissa, circus acrobat and troublemaker, are the secret last hope of a city beset by horror. A poisoner stalks the streets, leaving victims mad with terror—and then dead. Can the Black Terror be traced to a demon called Malphas? With their partnership threatened by rules and regulations, can Wild Boy and Clarissa uncover a cure in time to save the queen and the city?