In Paris, Robert Langton, a Harvard symbologist and Agent Sophie Neveu, a French cryptologist find the elderly curator of the Louvre, Jacques Sauniere, murdered in the museum covered with intriguing symbols and bizarre riddles, naked, spread like an eagle in Leonardo da Vinci’s famous painting, The Vitruvian Man. Robert and Sophie soon discover clues which leads them to the famous works of art of Leonardo da Vinci, the Mona Lisa. They find a key embossed with the symbol of the Priory Of Sion, a secret society in which Isaac Newton, Victor Hugo, Da Vinci, Botticelli and Sophie Neveu’s grandfather, Jacques Sauniere belonged to.

Together, Robert and Sophie work together in a quest to find the Holy Grail, which is in fact Mary Magdalene’s tomb or something that is related to it. They do not know that the Opus Dei centre is searching for exactly what they are searching for. Using Jacques Sauniere’s difficul clues, they are aware that if they do not succeed or if the Holy Grail falls in the wrong hands, the ancient truth will be lost forever…