A carriage bearing the Arnifour family crest brings a new case to Colin Pendragon: Lady Arnifour’s husband has been found dead and her niece in a coma. With the police suspecting the groundskeeper and his son, Lady Arnifour believes in their innocence. While investigating, Pendragon and Pruitt are also approached by a street urchin looking for his missing sister. Their search takes them from opium dens to Embassy Row, revealing a connection between the cases that is both unexpected and dangerous.