Summary: Chapter 16

Sophie thinks about the phone message she got from Saunière earlier that day. She and Saunière were estranged for over a decade after she saw him engaged in an act she found despicable. He wrote her letters and tried to explain what she had seen, but Sophie refused to have any contact with him.

The message Sophie got from Saunière sounded urgent. In it, he said they were both in danger, and he had to tell her the truth about what happened to her family. Sophie’s family died in a car accident when she was little. She thought her grandfather’s message was just a ploy to get her to talk to him. She did not call him back.

Sophie asks Langdon to explain why Saunière would want to meet with him, but he doesn’t know. She tries to convince Langdon to leave the museum with her and go to the American Embassy for protection while they figure out what happened to her grandfather. Langdon refuses to run. Fache calls Sophie’s cell phone, but she turns it off. Sophie looks out the window and wonders whether Langdon could make it out of the building by jumping.

Summary: Chapter 17

Fache informs Collet that the director of cryptography cracked the code—like Sophie, he believes it to be meaningless Fibonacci numbers. The director also revealed that he did not send Sophie over to the museum, and that Saunière was Sophie’s grandfather. Collet, like Sophie, believes that Saunière must have written the code in order to get his granddaughter involved in the case.

Fache and Collet continue to try to reach Sophie. An alarm rings, signaling a security breach in the men’s room. The two policemen see on the GPS screen that Langdon has apparently jumped out of the window.

Summary: Chapter 18

Collet sees the tracking dot go out of the window and then come to a complete stop. The police assume Langdon has committed suicide, but then the dot starts moving away from the building and down the road. Fache looks out the bathroom window and sees a huge flatbed truck moving away. Assuming that Langdon must have jumped onto the truck, Fache runs out of the building to apprehend him.

Meanwhile, Sophie and Langdon hide in the shadows of the museum. The narrator explains that Sophie broke the window using a garbage can and then threw the GPS tracker, which she had imbedded in a bar of soap, out the window and onto the truck. Once all of the police have left the building, Sophie tells Langdon to go down a side stairwell with her. Langdon is impressed with Sophie’s quick thinking.

Summary: Chapter 19

Silas enters Saint-Sulpice. Sister Sandrine offers to give him a tour of the church, but he refuses it. He asks her to go back to bed, saying he wants to pray and can show himself around. She agrees, but she is suspicious of him. Hiding in the shadows, she watches him pray, thinking that Silas might be the enemy she was warned about.

Summary: Chapter 20

As he tries to decipher Saunière’s message, Langdon realizes that everything in the message relates in some way to PHI, or 1.618, the number of Divine Proportion, starting with the Fibonacci sequence. He thinks of a lecture he gives about how PHI is the numerical proportion of many things in nature and in art, including the pentacle, the symbol of the sacred feminine.

Suddenly, Langdon realizes that the word portion of Saunière’s message is actually an anagram. He unscrambles it and gets: “Leonardo Da Vinci! The Mona Lisa!”

Analysis: Chapters 16–20

It is not surprising that Saunière would want to bring Sophie and Langdon together—as Brown demonstrates in this chapter, they make an effective team. Unlike the many sexist characters that populate the novel, such as Fache, Langdon clearly respects women. When Sophie figures out how to trick the police by embedding the tracking advice in a bar of soap and throwing it out the window, Langdon is humbled and impressed by her cleverness and quick thinking. But Langdon is not simply looking on in wonder; he pulls his own weight, breaking the code that neither Sophie nor anyone in her cryptography department could solve. Langdon is an academic and extremely book-smart, while Sophie is the one with the street smarts. She can think on her feet and wriggle out of difficult situations.

Brown introduces his characters’ backgrounds without breaking the narrative thread. By revealing that Sophie was not in contact with her grandfather because she was traumatized by something she witnessed him doing, Brown intentionally creates confusion. The novel is structured to make us sympathetic toward Saunière, the victim, but on the other hand, Sophie’s anger with him forces us to question his integrity.

Collet represents the neutral observer. He does not seem to have any ulterior motives, and unlike Fache, he has no personal investment in the case. Brown still has not revealed whether Fache’s interest in the job is motivated by the desire for a high profile case to secure his position, as Collett believes, or by a connection with the Opus Dei.