Florence, New Year's Day 1557. As dawn breaks, a painter is discovered lying on the floor of a church, stabbed through the heart. Above him, the paintings he laboured over for more than a decade. At his home, a hidden painting scandalously depicting Maria de Medici, daughter of the Duke and Duchess of Florence, as a naked Venus. Who is the murderer? Who is behind the painting? As the city erupts in chaos, Giorgio Vasari, the great art historian, is picked to lead the investigation. Letters fly back and forth carrying news of political plots and speculation about the killer's identity - between Maria and her aunt Catherine de' Medici, the queen of France; between Catherine and her scheming agents in Florence; and between Vasari and his friend Michelangelo. Meanwhile, the Pope is banning books and branding works of art immoral.