Prologue–Chapter 3Jacques Saunière is murdered in the Louvre, a museum in Paris, by an albino attacker, Silas, because he knows where a secret keystone is hidden. Robert Langdon, Harvard symbology professor, is in Paris on business. A policeman is sent to his room because he thinks he may have information about Saunière's death. Langdon planned to meet Saunière for a drink, but the meeting was cancelled. Langdon goes to the Louvre with the policeman and meets Bezu Fache, the police captain. Chapters 4–9 Fache shows Langdon Saunière's body, which is strangely positioned. Fache secretly suspects that Langdon is Saunière's killer. Meanwhile you are introduced to Manuel Aringarosa, the president of Opus Dei, a religious sect, I believe. He is traveling to Rome. Back in Paris, Langdon explains to Fache the significance of the way Saunière prepares before dying. There are other clues Langdon points out. Saunière wrote a message next to his body. It's a clue. Langdon suggests that Sauniere intended to organize his body in the shape of one of Da Vinci's famous drawings, The Vitruvian Man. Sophie Neveu, Saunière's niece and cryptologist, shows up at the museum claiming to have discovered the code. He tells Langdon to call the US Embassy but the number he gives him is his answering machine which tells Langdon he is in trouble. Chapters 10–15 Silas arrives and the church of Saint-Sulpice because it is here that Sauniere revealed the ancient secret lies to him. Langdon uses the bathroom to get away from Fache. Sophie meets Langdon in the bathroom to better explain her message to him. She tells him that her grandfather wanted her to find him. She tells him that her grandfather left them clues about something. Silas heads to the churchChapters 16-20Sophie and Langdon hide in the bathroom and the GPS device that was on Langdon out the window on a truck to make Fache think he jumped out the window but in reality they hide in the shadows. Once all the police are gone, 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 look for the painting.