Prologue–Chapter 3Jacques Saunière is murdered at the Louvre, a museum in Paris, by an albino attacker, Silas, because he knows where a secret keystone is hidden. Robert Langdon, professor of symbology at Harvard, is in Paris on business. A police officer is sent to his room because it is believed he might have information about Saunière's death. Langdon had planned to meet Saunière for drinks, but their meeting was canceled. Langdon goes to the Louvre with the policeman and meets Bezu Fache, the police captain. Chapters 4 to 9 Fache shows Langdon Saunière's body, which is strangely positioned. Secretly, Fache suspects Langdon of being Saunière's murderer. Meanwhile, we introduce you to Manuel Aringarosa, the president of Opus Dei, a religious sect, I think. He is on his way to Rome. Back in Paris, Langdon explains to Fache the importance of the way Saunière organized himself before dying. Langdon points to other clues. Saunière wrote a message next to his body. It's a clue. Langdon suggests that Saunière intended to arrange his body in the form of one of Leonardo da Vinci's famous drawings, The Vitruvian Man. Sophie Neveu, Saunière's granddaughter and cryptologist, shows up at the museum claiming to have discovered the code. She tells Langdon to call the American embassy but the number she gives him is her own answering machine which tells Langdon he is in trouble. Chapters 10 to 15 Silas arrives and the Saint-Sulpice church because it is there that Saunière entrusted him with the ancient secret. lies. Langdon uses the toilet to get away from Fache. Sophie meets Langdon in the bathroom to further explain her message. She tells him that her grandfather wanted her to find him. She tells him that his grandfather left them clues about something. Silas heads towards the church. Chapters 16 to 20. Sophie and Langdon hide in the bathroom and the GPS that was on Langdon through the window of a truck to make Fache believe that he had jumped out of the window, but they are actually hiding in the shadows. Once all the police officers have left, they go down a stairwell together. Silas enters the church to find the keystone. Langdon discovers that Saunière wanted them to look at the Mona Lisa. Chapters 21-25 Sophie tells Langdon to go to the embassy without her while she goes to get the painting..