Chapter 71
Chapter Characters:
Robert Langdon
Sophie Neveu
Sir Leigh Teabing

Chapter Summary:
Aboard the plane to England, Langdon and Teabing try to identify the mysterious inscription. Sophie identifies it as mirror writing, as Da Vinci used. , because her grandfather introduced her to the practice.

Chapter Themes:
The human world is encoded with meaning.
The centrality of human relationships, especially male-female relationships.
The influence of the past upon the present.

Chapter 72
Chapter Characters:
Robert Langdon
Sophie Neveu
Sir Leigh Teabing

Chapter Summary:
The inscription is English—and poetry—but ciphered. It reads:
"An ancient word of wisdom frees this scroll…and helps us keep her scatter'd family whole…a headstone praised by templars is the key…and atbash will reveal the truth to thee."

Langdon explains that "The Atbash Cipher is one of the oldest codes known to man," a Hebrew encoding system based on letter substitution.
As the chapter ends, Teabing has gone to get snacks, leaving Langdon and Sophie alone.

Chapter Themes:
The human world is encoded with meaning.
The centrality of human relationships, especially male-female relationships.
The influence of the past upon the present.

Chapter 73
Chapter Characters:
Bezu Fache

Chapter Summary:
At Bourget Airfield, Fache gets the Grail-seekers' destination in England (Kent), and calls ahead for local police help there.

Chapter 74
Chapter Characters:
Robert Langdon
Sophie Neveu

Chapter Summary:
Alone again, Langdon and Sophie discuss the rift between Sophie and her father. Langdon speculates accurately that Sophie had stumbled into a sex ritual involving her grandfather, the Hieros Gamos, saying "Historically, intercourse was the act through which male and female experienced God. The ancients believed that the male was spiritually incomplete until he had carnal knowledge of the sacred feminine." Sophie tumbles back into her memories, and how disturbed she was by what she'd seen: her masked grandfather (who she recognized via a birthmark on his shoulder) making love to a masked woman, while a crowd of masked and robed figures chanted.

Chapter Themes:
The human world is encoded with meaning.
The centrality of human relationships, especially male-female relationships.
The influence of the past upon the present.

Chapter 75
Chapter Characters:
Bezu Fache
Bishop Aringarosa

Chapter Summary:
After finishing his call from Fache, Bishop Aringarosa bribes his pilot to change destinations and take him to London.

Chapter Themes:
The power of belief, and the need to believe.

Chapter 76
Chapter Characters:
Robert Langdon
Sophie Neveu
Sir Leigh Teabing

Chapter Summary:
Teabing returns and together the three determine the meaning of the line about the headstone: a stone head of the pagan fertility god Baphomet.

Chapter Themes:
The human world is encoded with meaning.
The centrality of human relationships, especially male-female relationships.
The influence of the past upon the present.

Chapter 77
Chapter Characters:
Robert Langdon
Sophie Neveu
Sir Leigh Teabing

Chapter Summary:
They work together with the Atbash cipher to figure out how to spell Baphomet in Hebrew, then convert Sophie's name to "S-O-F-I-A" because "Sophia literally means wisdom in Greek. The root of your name, Sophie, is literally a 'word of wisdom.'" This code both shows how much Sophie's grandfather loved her, and how much her identity is shaped by the past.

Chapter Themes:
The human world is encoded with meaning.
The centrality of human relationships, especially male-female relationships.
The influence of the past upon the present.

Chapter 78
Chapter Characters:
Robert Langdon
Sophie Neveu
Sir Leigh Teabing

Chapter Summary:
The three open the cryptex, only to find a second, smaller cryptex inside, this one black to the first's white. Another four line poem of clues is inside, the first line of which reads,...