Fache calls the US Embassy, trying to retrieve Langdon’s message, but the embassy informs him that the automated message system was replaced two years ago. He pulls out his own cell phone and dials the number Langdon called earlier. Seething, he realizes that the message was not from the embassy but from Agent Neveu.

Langdon and Sophie enter the Salle des Etats, Sophie sweeping the floor with a black light pen, searching for any additional clues left by her grandfather. Langdon tingles with excitement at his proximity to one of the world’s finest works of art, a painting Da Vinci regarded as his finest. However, his regard may have had more to do with the secrets buried under the paint than with its artistic merit. One such secret refers to the Egyptian god and goddess of fertility: Amon and Isis (once known as L’Isa), an anagram for Mona Lisa.

As Langdon and Sophie search the gallery, Langdon notices something caught in the glimmer of the black light: six words written across the plexiglass protecting the Mona Lisa.

Fache calls Collet. He informs him that Sophie has alerted Langdon to the tracking device and that she and Langdon are likely still inside the building.