Sister Sandrine realizes that all four of the men she was instructed to call in this emergency are dead. Silas finds her and demands to know where the keystone is. She tells him that secret is guarded by others. In a fit of rage, Silas murders her.

Langdon and Sophie speed towards the Embassy. Sophie thinks about the key she saw as a child, which is now in her pocket, and realizes that it was created by lasers and impossible to duplicate. She thinks about the last time she saw her grandfather. She was planning to surprise him by coming home from school early for spring break. When she did not find him at his Paris home, she figured he must be at his country house. When she arrived she saw many expensive cars parked outside, but saw no other signs of the party she figured her grandfather must be hosting. Inside, she heard voices chanting from below. A tapestry that normally hung in the living room was pushed to the side, exposing a secret door.

Behind the door Sophie found a secret basement. She was profoundly disturbed by what she encountered there--men dressed in black and women dressed in white performing some kind of ritual. Horrified by what she saw, Sophie ran upstairs. Before she left, she wrote her grandfather a note telling him she had seen what he was doing and warning him not to contact her. Langdon shakes Sophie from her thoughts, shouting that the road to the Embassy has been sealed off.

As she speeds away Sophie hands Langdon the infamous key, which her grandfather had left for her behind the Madonna of the Rocks. Sophie drives them to a train station.

As Aringarosa is picked up from the airport, he thinks about the last time he visited Rome. Aringarosa is not a fan of the current Pope. He believes the Holy Father is trying to rewrite the laws of the church to make it more modern. Five months earlier, the Pope asked Aringarosa to visit him for a confidential meeting. Aringarosa was shocked by what the Pope told him.

Sophie tells Langdon to purchase two train tickets with his credit card, knowing that the purchase will be traced. She then takes Langdon to the back of the station and gets into a taxi, which she hired when they arrived. Langdon and Sophie talk more about the key. They discover that her grandfather has written an address on it. Sophie asks the driver to take them to the address.

Notes

This section really portrays Silas as a fanatic. Silas has murdered four men already on the Church's behalf, but according to a carefully constructed plan. Silas murders Sister Sandrine in a rage because he believes she has betrayed the Church. Silas has proven that he is too willing to please the Church. He has lost his ability to think rationally. Some might argue that his interaction with Opus Dei, which requires corporeal mortification and constant sacrifice, adds to his characterization as a fanatic.

We also learn more about Bishop Aringarosa. Religiously, he is very conservative, much like Fache. These men are from the old school; they do not believe women should have any power and they do not like things to change. These beliefs will motivate many of their decisions throughout the novel.