Gabriel Allon has been awarded a commission to restore one of the most important paintings in Venice. But when he discovers the body of a mysterious woman floating in the waters of the Venetian Lagoon, he finds himself in a desperate race to recover a lost masterpiece by Leonardo da Vinci. The painting, a portrait of a beautiful young girl, has been gathering dust in a storeroom at the Vatican Museums for more than a century, misattributed and hidden beneath a worthless picture by an unknown artist. Because no one knows that the Leonardo is there, no one notices when it disappears one night during a suspicious power outage. No one but the ruthless mobsters and moneymen behind the theft -- and the mysterious woman whom Gabriel found in a watery grave in Venice. A woman without a name. A woman without a face. The action moves at breakneck speed from the galleries and auction houses of London to an enclave of unimaginable wealth on the French Riviera -- and, finally, to a shocking climax in St. Peter's Square, where the life of a pope hangs in the balance.