Gabriel Allon, the wayward son of Israeli intelligence, has taken refuge behind the walls of the Vatican, where he is restoring one of Caravaggio's greatest masterpieces. But while working early one morning, he is summoned to St. Peter's Basilica by his friend and occasional ally Monsignor Luigi Donati, the all-powerful private secretary to his Holiness Pope Paul VII. The body of a beautiful woman, a curator from the antiquities department, lies smashed and broken beneath Michelangelo's magnificent dome. The Vatican police suspect suicide, though Gabriel, with his restorer's eye and flawless memory, believes otherwise. So, it seems, does Donati. He calls upon Gabriel to use his matchless talents and experience to quietly pursue the truth. Gabriel soon learns that the dead woman had uncovered a dangerous secret-a secret that threatens a global criminal enterprise that is looting timeless treasures of antiquity and selling them to the highest bidder.