After reluctant spy Alvise Marangon is arrested in a tavern brawl, he is summoned to meet the Missier Grande, head of the city's powerful secret service. Rather than being expelled from the city, he is coerced into a top-secret investigation of the mysterious death of one of the service's agents and the existence of a mysterious secret society. Formed by four rakish noblemen, it is known as the Four Horsemen and dates back to the Ottoman Empire. As Alvise delves into the case, he finds all the hallmarks of assassination and corruption, and is soon profoundly out of his depth and on the run.
In this excellent sequel, Dowling successfully builds on the clever premise he introduced in 2016's Ascension, his first novel featuring 18th-century Venetian spy Alvise Marangon the premise being that Dowling has uncovered a folder buried in the Venetian state archives recounting Alvise's exploits. Alvise divides his time between working as a tour guide, principally for English travelers, and serving as a confidential agent for the Missier Grande, the man responsible "for all matters of common criminality." The Missier Grande charges Alvise with investigating the death of a fellow operative, Paolo Padoan, who apparently fell from his roof by accident. A few days earlier, Paolo reported his discovery of a mysterious secret society, the Four Horsemen, some of whose members may have belonged to noble families. Apart from looking into the possibility that Paolo was murdered, Alvise must tread carefully to avoid incurring the wrath of the Missier Grande's archrival, the Council of Ten, in particular the three Inquisitors on the council who are in charge of inquiries related to state security. Dowling's lead's wry sense of humor is a plus.