Did they truly understand the danger? he wondered. With a chill he remembered that special knobs from headquarters were in the county. They didn't come for dead boys or a missing teacher. They had come for foreign subversives. They could arrive by helicopter at any time- the next hour, the next minute. He surveyed the resolute scientists as they returned to their work. Jakli understood. Surely Najan understood. If the knobs landed in airships they would have incendiary bombs, special bombs that could suck all the oxygen out of a place like this. They might take the trouble to march through and shoot each of them in the head. Or they might just seal the cavern up and let them all die more slowly. The knobs would have many options if they discovered Sand Mountain, but none would include taking prisoners.

"Your son," Shan suddenly remembered. "Your son is here," he said, instantly regretting the alarm in his voice.

Abigail Deacon searched his eyes for a moment. "What about him?" she asked.

"Is he here, at Sand Mountain?"

The American looked at Jakli. "He's safe. Not here, in the Kunlun."

"What do you mean?" Shan asked.

"With some herders. Lau arranged it, as if he were another of her orphans. One of the border families, a shadow clan, Lau called them. She said it was the safest place he could be."

"The zheli?" Jakli gasped. "Your son is with the zheli?"

Abigail Deacon didn't know, Shan realized with a chill as the woman looked at them in confusion. She had sent her son to safety in the mountains. But now the American boy was on the zheli death list.

Shan touched his finger to his left temple, where a low throbbing had started again. Before he could speak Jakli's hand was on his arm, pulling him away, guiding him back toward his pallet.

"They need to understand. Their son is in grave danger," he said through his pain as she led him down the tunnel.

"The family he's with, they're wary as leopards. No one sees them unless they want to be seen," she said but did not sound convinced. She gave him more water and lit the small lamp by the pallet, then left him to sleep.

He did sleep, at least he thought he slept, but not for long. Sounds in the tunnel brought him to full wakefulness, the throbbing not gone but subsided. He picked up the clay lamp and rose, then listened to the sounds and returned the lamp to the floor. There were voices speaking in the herders' tongue. He could not recognize the words, but they were nervous and harried, filled with the urgency of a task at hand.

Shan ventured toward the sounds, edging around the corner where the tunnel entered the chamber, where he saw two men, wearing the woolen vests and caps of herdsmen, carrying something into one of the meditation cells. A third, dressed in the same garb, held a bright kerosene lantern. The bundle carried by the first two was long and narrow. They carried it gingerly, as if it could break.

The men disappeared into the cell, then quickly emerged without their bundle and jogged down the corridor. He was about to move toward the cell to investigate when another light appeared. Jacob Deacon approached, carrying a bag like a doctor's kit, accompanied by Dr. Najan, who still wore his lab coat, and carried a bright battery-powered lamp. Speaking in low tones, they entered the same cell. Shan inched along the wall for a better view. Deacon was kneeling at the blanketed bundle left by the herdsmen, with a large syringe. He pressed it into an opening in the blanket, handed it to Najan, and accepted a second syringe from Najan. The American repeated the process with the syringe, then both men quickly rose and retreated back into the darkened tunnel.

He realized now that it was a person they had carried into the cell, an ill person who needed the American's medication. He waited five minutes, then retrieved his lamp and returned to the entrance of the cell. He recalled that this was where he had previously seen two sleeping forms. Were they all sick, perhaps injured like Shan in the karaburan? He stepped into the cell and saw three blanketed forms on the floor.

Each was wrapped in a heavy felt blanket, with a small roll of felt for a pillow. On the blanket of each an embroidered scarf had been carefully laid, smoothed out so its pattern of leaping horses and large trees was clearly visible. Careful not to wake the sleepers, he moved the lamp closer to the first figure and froze. There was something terribly wrong with the face. The man had no nose. With a trembling hand Shan moved the lamp directly above the face. He had no eyes. And the man, Shan realized as he studied the dried, mummified features, had not seen for centuries. The sand and dryness preserved things, Abigail Deacon had said. He had thought she was only talking about textiles. Shan gently pulled the blanket open to reveal a brown twill robe and understood how she received her textile samples. The burial clothes, worn by the mummies of the Taklamakan.

After the first moment of fright, Shan felt no fear, no revulsion. Quickly he looked at the other two figures, a woman with long brown hair in two braids, in the fashion of Niya Gazuli, and a man so complete, so well preserved he appeared in the dim light to be sleeping. The man was extraordinary, a visitor from a lost world. His face, though leathery, was light in color, and his thick, long, dark hair had a distinctly reddish hue, as did the man's thin beard. A cord of woven multicolored yarn connected his wrists, placing his long, delicate fingers in a reverent repose. He wore a heavy woolen shirt with cuffs that reminded Shan of the strip he had seen in the laboratory. On his feet were boots of thin leather, perhaps deerskin, and felt leggings extended to his knees.

He meant to leave, to go on to avoid detection and not to disturb the mummies further, but something held him back. He dropped to his knees by the bearded man and with a slow, tentative motion touched the cloth of his sleeve. Perhaps the man was a builder of Karachuk, Shan thought with a strange excitement. Perhaps he had plucked an apricot and sat to eat it in the shadow of the reclining Buddha. The serene face of the dead man seemed to hold great wisdom, and the man seemed to be challenging Shan to discover it.

He did not know how long he knelt, contemplating the figures. Eventually he became aware of cigarette smoke. He looked up to see Dr. Najan.

"You've met our silent partners," Najan observed quietly.

"How is it possible? Where-"

"The tracks of all the dead rivers are well known. All the old settlements were on the rivers, that's where we always look. The oldest burial grounds can be easily identified, because burials were made inside circles of logs, built like a small fortress. After a big storm, sometimes a ring of logs is exposed. There are a few old Kazakhs and Uighurs who know the desert ways, who aren't afraid to camp in the desert at night."

"With three, you are able to determine so much?"

"Three? These are only the latest, exposed after the karaburan. Over fifty have been collected. Another thirty have been examined in situ."

"Fifty mummies are here?"

"We take our samples, take photos and videos, then return them to their sleep. If we feel the site has become known to looters, we bury them in a new, secret location." As the scientist gazed upon the three mummies, Shan saw a strange, sad pride in his eyes. "We have words we read over them, to apologize for disturbing their rest, to let them know we have not forgotten."

Shan remembered the syringes of Deacon. "You take samples of tissues," he said, "not just samples of textiles."