“Are you all right?” she asked.

Silent, Natalie stared straight ahead. Mikhail was in the passenger seat next to the driver. The second Toyota, the one carrying Keller and Jean-Luc Martel, was about a hundred meters ahead. Behind them the road was empty. Even the Renault, the one that had been following them since Fez, was nowhere to be seen.

The palm groves receded, the landscape turned harsh and rocky. At Rissani the paved road ended, and soon the great sand sea of Erg Chebbi appeared. The village of Khamlia, a cluster of low mud-colored houses, lay at the southern end of the dunes. There they left the main road and turned onto a pitted desert track. Natalie monitored their progress on her mobile; they were a blue dot moving eastward across an uninhabited land toward the Algerian border. Then suddenly the blue dot froze as they ventured beyond cellular service. Mikhail had brought a satellite phone for just such an eventuality. It was behind Natalie, in the same bag as the Beretta.

For half an hour they drove as all around them the great wind-sculpted dunes turned brick-red with the gathering dusk. They passed a small encampment of nomadic Berbers who were boiling water for tea at the entrance of a black camel-hair tent. Otherwise, there was not another living soul. Only the mountainous dunes and the vast sheltering sky. The emptiness was unbearable; Natalie, despite the close proximity of Olivia and Mikhail, felt painfully alone. She scrolled through the photos on her phone, but they were Madame Sophie’s memories, not hers. She could scarcely recall the farm at Nahalal. Hadassah Medical Center, her former place of employment, was all but lost to her.

At last, the camp appeared, a cluster of colorful tents arranged in the cleft of a dune. Another white Land Cruiser had arrived before them; Natalie supposed it was for the staff. She allowed one of the robed porters to take her bags, but Mikhail, adopting the supercilious manner of Dmitri Antonov, succeeded in carrying his into the camp unassisted. There were three tents arranged around a central court, and a fourth a short distance away with showers and toilets. The court was carpeted and adorned with large pillows and a pair of couches along a low-slung table. The tents were carpeted, too, and furnished with proper beds and writing tables. There was no evidence of electricity, only candles and a large fire in the court that threw shadows on the face of the dune. Natalie counted six staff in all. Two were visibly armed with automatic rifles. She suspected the others were armed as well.

With sunset, the air turned cooler. In her tent Natalie slipped on a fleece pullover and then went to wash for dinner. Olivia joined her a moment later.

Quietly, she asked, “Why are we here?”

“We’re going to have a lovely dinner in the desert,” answered Natalie.

Olivia’s eyes met Natalie’s in the mirror. “Please tell me someone is watching us.”

“Of course they are. And listening, too.”

Natalie went out without another word and found the table laid with a lavish Moroccan feast. The staff kept their distance, appearing every so often to refill their glasses from on high with sickly-sweet mint tea. Nevertheless, Natalie, Mikhail, and Christopher Keller held fast to their cover. They were Sophie and Dmitri Antonov and their friend and associate, Nicolas Carnot. They had settled in Saint-Tropez earlier that summer and after a fitful courtship had made the acquaintance of Jean-Luc Martel and his glamorous not-quite wife, Olivia Watson. And now, thought Natalie, they were all five at the very end of the earth, waiting for a monster to rise from the night.

Maimonides . . . So good to see you again . . .

Shortly after nine o’clock the staff cleared away the platters of food. Natalie had scarcely eaten. Alone, she walked to the edge of the camp to smoke one of Madame Sophie’s Gitanes. She stood where the firelight ended and the darkness began. She stood, she thought, at the earth’s sharp edge. Forty or fifty yards into the desert, one of the armed staff members kept watch. He wore the white robes and headdress of a Berber tribesman from the south. Pretending not to see him, Natalie dropped her cigarette and started across the sand. The guard, startled, blocked her path and gestured for her to return to the camp.

“But I wish to see the dunes,” she said in French.

“It is not allowed. You can see them in the morning.”

“I prefer now,” she answered. “At night.”

“It is not safe.”

“So you’ll come with me. Then it will be safe.”

With that, she set off across the desert again, followed by the Berber guard. His garments were luminous; his skin, black as pitch, was indistinguishable from the night. She asked his name. He told her he was called Az?lay. It meant “the man with nice eyes.”

“It is true,” she said.

Embarrassed, he looked away.

“Forgive me,” said Natalie.

They walked on. Overhead, the Milky Way glowed like phosphorus powder, and a minaret moon shone hot and bright. Before them rose three dunes, ascending in scale from north to south. Natalie removed her shoes and, trailed by Az?lay the Berber, climbed the highest dune. It took her several minutes to reach the summit. Exhausted, she dropped to her knees in the warm, soft sand to catch her breath.

Her eyes searched the land. To the west a thin strand of lights stretched intermittently from Erfoud, through the palm groves of the Tafilalt Oasis, to Rissani and Khamlia. In the east and south there was only empty desert. But to the north Natalie glimpsed a pair of headlights bobbing toward her through the dunes. After a moment the lights vanished. Perhaps, she thought, it had been a mirage, another dream. Then the lights reappeared.