Langdon, the novel’s protagonist, anchors the story. He is likable, capable, and goodhearted. Langdon is trustworthy, as is Sophie, his female counterpart and love interest. This trustworthiness makes him stand out in a narrative in which the author casts doubt on the motivations of every major character except Langdon and Sophie. In the novel’s many moments of uncertainty, Langdon’s presence is consistently reassuring.

Although he is seen as a sex symbol in the academic world, Langdon is clumsy and inept with guns and weapons and lacks resolve when it comes to planning and executing action. He would rather think about codes and symbols than figure out how to escape the Louvre under the eyes of policemen. For this reason, he is balanced well by Sophie, who transforms his intellectual abilities into survival skills that are applicable to real life.