Robert Langdon's awoken by an unexpected phone call just after midnight. It's the Hotel Ritz Paris front desk, alerting him that he has a visitor.
Despite his efforts to politely decline (it's really late, he was asleep, and he didn't invite anyone over), the concierge insists that his visitor is a very important man and won't take no for an answer.
Langdon's assuming that his visitor's probably someone who's upset with that night's lecture: he'd presented on pagan symbolism hidden in Chartres Cathedral. Or maybe it's someone who recognizes him from his brush with disaster last year at the Vatican.
Recently, Boston Magazine published a really embarrassing piece about Langdon (calling him one of the city's top ten most intriguing people) which has made his reluctant celebrity status even worse.
The concierge calls back, just to let Langdon know that his visitor is on his way to his room. Yikes.
His "visitor" is Lieutenant Jérome Collet, of the Direction Centrale Police Judiciaire. (The DCPJ is like the French FBI. This is not good.)
Langdon wants to know why Collet's asking for his help with a private matter after midnight.
Collet hands Langdon a picture of Jacques Saunière. They had been supposed to meet for drinks after Langdon's lecture, but he'd never shown up. Now Robert knows why.
Saunière's body's positioned in a strange way, and there are symbols, too—which is why, combined with his name in Saunière's date book, the police have sought Langdon out.