And so it was that as he made his way through the quiet streets of Rome, he was trailed by no fewer than three probationers of varying skills from the Italian security service. His route presented them with few challenges and no surprises. It bore him westward across the ancient center of the city and terminated, as usual, at St. Anne’s Gate, the business entrance of the Vatican. Because it was technically an international frontier, the watchers had no choice but to entrust the restorer to the care of the Swiss Guard, who admitted him with only a cursory glance at his credentials.

The restorer bade the watchers farewell with a doff of his flat cap and then set out along the Via Belvedere, past the butter-colored Church of St. Anne, the Vatican printing offices, and the headquarters of the Vatican Bank. At the Central Post Office, he turned to the right and crossed a series of courtyards until he came to an unmarked door. Beyond it was a tiny foyer, where a Vatican gendarme sat in a glass box.

“Where’s the usual duty officer?” the restorer asked in rapid Italian.

“Lazio played Milan last night,” the gendarme said with an apathetic shrug.

He ran the restorer’s ID badge through the magnetic card swipe and motioned for him to pass through the metal detector. When the machine emitted a shrill pinging, the restorer stopped in his tracks and nodded wearily at the gendarme’s computer. On the screen, next to the restorer’s unsmiling photograph, was a special notice written by the chief of the Vatican Security Office. The gendarme read it twice to make certain he understood it correctly, then, looking up, found himself staring directly into the restorer’s unusually green eyes. Something about the calmness of his expression-and the hint of a mischievous smile-caused the officer to give an involuntary shiver. He nodded toward the next set of doors and watched intently as the restorer passed through them without a sound.