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

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.