"The Da Vinci Code," a mystery thriller novel by Dan Brown, was first published in 2003. The story follows Robert Langdon, a Harvard symbologist, and Sophie Neveu, a French cryptologist, as they investigate the murder of the curator of the Louvre Museum, Jacques Saunière. The investigation uncovers a series of hidden clues and messages within some of Leonardo da Vinci's most famous works, leading them on a quest to uncover a secret that has been protected by a covert society for centuries.