This book describes the attempts of Robert Langdon, Professor of Religious Symbology at Harvard University, to solve the murder of renowned curator Jacques Saunière of the Louvre Museum in Paris. A baffling cipher is found near his body. Saunière's granddaughter, Sophie Neveu and Langdon attempt to sort out the bizarre riddles and are stunned to discover a trail of clues hidden in the works of Leonardo Da Vinci.
The unraveling of the mystery requires solutions to a series of brain-teasers, including anagrams and number puzzles. The ultimate solution is found to be intimately connected with the possible location of the Holy Grail and to a mysterious society called the Priory of Sion, as well as to the Knights Templar. The story also involves the Roman Catholic organization Opus Dei.