In the tradition of The Alienist and The Devil in the White City comes a gripping, atmospheric tale of murder and the art of crime solving. Paris, 1889: in anticipation of the World's Fair and the opening of Monsieur Eiffel's tower, a society of the world's most famous detectives convenes as a single body for the very first time. Sent in place of a conspicuously absent Renato Craig, founding member of The Twelve, his novice assistant Sigmundo Salvatrio arrives, bearing a secret message for the brilliant, brooding Viktor Arzaky, Craig's best friend and the society's cofounder. When one of The Twelve is discovered murdered at the Tower's base—the first in a series of grisly slayings—it falls to Arzaky and Salvatrio, the last remaining student of Craig's famed Academy for Detectives in Buenos Aires, to find and stop the killer. But what the two discover as they race around fin-de-siècle Paris—encountering secret societies, philosophical puzzles, and an imperiled, dangerously beautiful woman—has shattering consequences that will alter the fate of their precious brotherhood forever.