Venice, June 2020. The city has returned to the Venetians during a merciful pause in the Covid pandemic. Yet Dominic Vicari, a British private investigator haunted by loss, has travelled across Europe to the tiny island of San Francesco del Deserto. The ancient monastery there, it is said, was founded by St Francis himself in the 13th century. Its population now consists of five Franciscan brothers and three pilgrims on retreat. Or, rather, two pilgrims and a dead man. Nathan Sutherland is called in when Vicari's broken body is found at the base of the campanile, his death seemingly nothing more than a terrible accident. But Nathan isn't so sure and sets out on an investigation that will reunite him with an old friend and an old adversary, and the discovery of a terrible secret hidden at the heart of the lagoon.