Langdon suspects they are on the hunt for a breathtaking historical secret, one that has proven through the centuries to be as enlightening as it is dangerous. The stakes are raised when Langdon uncovers a startling link: The late curator was involved in the Priory of Sion-an actual secret society whose members included Sir Isaac Newton, Botticelli, Victor Hugo, and Da Vinci, among others. As Langdon and a gifted French cryptologist, Sophie Neveu, sort through the bizarre riddles, they are stunned to discover a trail of clues hidden in the works of Da Vinci-clues visible for all to see and yet ingeniously disguised by the painter. The elderly curator of the Louvre has been murdered inside the museum, a baffling cipher found near the body. While in Paris on business, Harvard symbologist Robert Langdon receives an urgent late-night phone call.