After a cryptic letter summons Adrian West and Nick Harper to Venice, a revelation from the past shatters Adrian's world... They must pick up the pieces to follow a trail of cryptic clues, unraveling the threads of a conspiracy rooted deep in Venetian history. In a desperate race from the canals of Venice, the ancient streets of Dubrovnik, to the Byzantine-era relics of Istanbul, Adrian and Nick must prevent a clandestine society from carrying out a lethal, centuries-old agenda that could spell humanity's extinction...