Just then a dark-gray Mercedes car nosed out of a cross street and blocked their path. Yaakov slammed on the brakes to avoid a collision, then blew his horn and waved at the Mercedes to get out of the way. The driver, a young Arab-looking man, stared coldly back at Yaakov and punished him for his recklessness by inching slowly out of their path. By the time Yaakov was under way again, Khaled had turned the corner and disappeared from Gabriel’s sight.

Yaakov sped to the end of the street and turned left, into the boulevard André Aune. It rose sharply away from the old port, toward the looming tower of the Church of Notre Dame de la Garde. Khaled had already crossed the street and at that moment was slipping into the entrance of a covered passageway. Gabriel had used the computer program to memorize the route of every street in the district. He knew that the passageway led to a flight of steeply pitched stone steps called the Montée de l’Oratoire. Khaled had rendered the motorbike useless.

“Stop here,” Gabriel said. “Don’t move.”

Gabriel leapt from his bike and, with his helmet still on his head, followed the path Khaled had taken. There were no lights in the passage, and for a few paces in the center Gabriel was in pitch darkness. At the opposite end he emerged back into the dusty pink light. The steps began—wide and very old, with a painted metal handrail down the middle. To Gabriel’s left was the khaki-colored stucco facade of an apartment house; to his right a tall limestone wall overhung with olive trees and flowering vines.

The steps curved to the left. As Gabriel came around the corner he saw Khaled again. He was halfway to the top and bounding upward at a trot. Gabriel started to draw the Barak but stopped himself. At the top of the steps was another apartment building. If Gabriel missed Khaled, the errant round would almost certainly plunge into the building. He could hear voices through his earpiece: Dina asking Yaakov what was going on; Yaakov telling Dina about the car that had blocked their way and the flight of steps that had forced them to separate.

“Can you see him?”

“No.”

“How long has he been out of sight?”

“A few seconds.”

“Where’s Khaled going? Why is he walking so far? Where’s his protection? I don’t like it. I’m going to tell him to back off.”

“Leave him to it.”