Sophie Reveals the Frame-Up

Langdon follows Sophie's instructions and goes to the men's room at the end of the Grand Gallery. Sophie follows him and reveals that he is under 'surveillance cachée' and is Fache's primary suspect. She shows him a GPS tracking dot planted in his jacket and a photograph of the complete message on the floor, which includes a fourth line: 'P.S. Find Robert Langdon.' Sophie explains that the message was meant for her, as P.S. stands for 'Princesse Sophie,' her grandfather's nickname for her. She tells Langdon that Jacques Saunière was her grandfather.