The book starts out with the murder of Jacques Sauniere. Robert Langdon is then called in to “help” with the investigation of the murder, but he is actually the prime suspect. Sophie Neveu is called in to help with the murder, and she knows that they want to arrest Robert Langdon. She is sure that Robert Langdon did not commit the murder, so she secretly lets him know that Bezu Fache’s only intention is to arrest him. They trick Bezu Fache into thinking he escapes through the window, and their companionship starts there. They both work together to find out who murdered Jacques Sauniere, and to decode the message he left them before he died. At first, Langdon is not sure if he likes Neveu, but he soon realizes that he is going to need her cryptology skills to figure out the message Jacques Sauniere is trying to give them. They work together throughout the whole novel, trying to find the Holy Grail and keeping from the Opus Dei (the word of God). They work together, and by the end of the book they are very good friends.
At the beginning of Sophie Neveu’s life, she had a very good relationship with her Grandfather Jacques Sauniere. He was her caretaker, because her family “died” (that is what she was told) in a car accident. They were very good friends until one day Sophie came home from college early, and walked in on her Grandfather participating in a religious sex ceremony that she obviously did not approve of. Although he sent her many letters, she did not talk to him for years. She actually didn’t talk to him until right before he died. Towards the end of the novel, she wishes she did not completely block him out of her life.
After Robert Langdon realizes that he was wanted for the murder of Jacques Sauniere, he seeks refuge at former British royal historian Leigh Teabing’s estate. Leigh Teabing’s life’s passion is the Grail. About fifteen years before the start of the novel, he moved to France to search its churches in hopes of finding the Grail. He had also written books on the keystones and the grail. Langdon figured that Teabing would be the perfect person to help him find the Grail; because he probably doesn’t watch TV (the search for Langdon is all over the news) and because of his knowledge of the Grail. Teabing joins Langdon and Neveu in their search for the Grail, but later turns against them with his own interests in mind.
Simon is a character who was taken in by the Opus Dei at a young age, after committing a murder. Since then, he has been an extremely faithful member of the Opus Dei. In the novel, the Opus Dei is seeking the Holy Grail. Simon helps them in their quest, and even kills the four main members of the Priory of Sion (the Senechaux, one of whom is Jacques Sauniere). Everyday, he wears a cilice for at least two hours (some days longer) to show his commitment to the Opus Dei. A cilice is belt with spikes that dig into your skin. This is obviously incredibly painful, and requires a lot of dedication to do it for seemingly no reason at all but to show loyalty to the group he belongs to. In the end, Simon is eventually killed while doing work for the Opus Dei.
The last relationship is involving the Holy Grail (and the knowledge of its location) and the Priory of Sion. There are four top members in the Priory of Sion, and nobody including the other members of the Priory of Sion knows who they are. Sophie Neveu’s Grandfather Jacques Sauniere is one of these top four members, known as the senechaux. The senechaux are the only people who know the location of the Holy Grail, and they are instructed to not tell anyone except for someone who is replacing one of the previous senechaux. The reason there is four of them is in case one dies. If they are threatened to be killed in exchange for the information about the Grail’s whereabouts, they all have a story set up to tell the person. Unfortunately, Silas murders all four of the senechaux, so nobody knows the location of the Holy Grail. This is the reason Jacques Sauniere leaves clues that lead to the Grail for Neveu and Langdon.
