While in Paris, Harvard symbologist Robert Lagndon is awakened by a phone call in the dead of the night. The elderly curator of th Louvre has been murdered inside the museum, his body and the floor around him covered in baffling symbols. As Langdon and a gifted French cryptologist, Sophie Neveu, sort through the bizarre riddels, they are stunned to discover a trial of clues hidden in the works of Leonardo Da Vinci - clues visible for all to see and yet ingeniously disguised by the painer. Even more starling, the late curator was involved in the Priory of Sion - an actual secret society whose members included Sir Isaac Newton, Victor Hugo, and Da Vinci, among others - and he guarded a breathtaking historical secret. Unless Langdon and Neveu can decipher the labyrinthine puzzle - while avoiding the faceless adversary who shadows their every move - the explosive, acient truth will be lost forever.