A thriller novel by Dan Brown, centered around a murder at the Louvre Museum in Paris and a subsequent investigation involving symbologist Robert Langdon and cryptologist Sophie Neveu. The pair must decipher hidden clues within Leonardo da Vinci's art and other historical texts to uncover a secret society's long-guarded truth about the Holy Grail and the lineage of Jesus Christ. The novel explores themes of faith, history, and the tension between science and religion.