Legendary spy and art restorer Gabriel Allon is in Venice repairing an altarpiece by Veronese when he receives an urgent summons from the Italian police. The eccentric London art dealer Julian Isherwood has stumbled upon a chilling murder scene in Lake Como, and is being held as a suspect. To save his friend, Gabriel must track down the real killers and then perform one simple task: find the most famous missing painting in the world.