Feng frowned but began to inch the truck forward.

Moving up the slope, Shan tried to piece together the geography. The skull cave was less than a mile away. Was this the Americans' back door to the skull cave? Had Fowler and Kincaid been so foolish as to return to the shrine? As he neared the top he heard a peculiar sound. Like bells, he thought. No, drums. A few feet further he realized it was rock and roll music. As he reached the crest he crouched and dropped back. There was a truck, but it was not the Americans'. It was bright red.

Calming himself, he edged his head above the rocks. It was the big Land Rover that Hu had been driving, but the figure at the wheel, tapping in time to the music, was too tall to be Hu.

It made no sense to park there. There was no one else to be seen, no one to wait for. There was not even much landscape to survey, for the rock outcropping cut off much of the view down the ridge.

Slowly, unconsciously, Shan's curiosity forced him to rise. There were fresh mounds of dirt behind the rear wheels, and a huge five-foot boulder in front of the vehicle, balanced precariously close to the lip of a bank that dropped sharply down to the road. Suddenly the man inside straightened and looked intently at the track below. Their own truck was coming into view. The figure inside the Land Rover raised his fist as though in victory and gunned the motor.

"No!" Shan screamed, and ran toward the truck. Its wheels were spinning, throwing more dirt into the air. The boulder was beginning to move.

He launched himself through the cloud of dust, pounding violently on the driver's window. The man turned and stared dumbly. It was Lieutenant Chang.

Shan could see him reaching for the gear shift. The truck seemed to ease back as Chang fumbled with the controls, then lurched forward. In one violent heave the boulder and the truck both flew over the bank.

As if in slow motion Shan watched Feng stop, then jump out of their truck with Yeshe just as the boulder hurled past them and disappeared over the edge. The Land Rover, airborne, struck the bank on its side and began to roll down the precipitous slope, glass popping, metal groaning, its wheels still whirling. It hit the road in the middle of a roll and landed on the driver's side in a cloud of dust, with the front half hanging over the chasm.

Shan, breathless, reached the road just as an arm rose through the shattered passenger's window. Chang, his forehead smeared with blood, appeared in the window and began to pull himself up. The music was still playing.

Lieutenant Chang stopped moving and shouted for Feng, who stood ten feet away. As he did so there was a groan of metal and something gave way. Chang screamed as the vehicle sank another foot over the edge and stopped.

Anger grew on Chang's face. "Sergeant!" he bellowed. "Get me-"

He never finished. The Land Rover abruptly tipped and disappeared from view. They could still hear the music as it fell.

Not a word was spoken as they backtracked down the ridge and onto the main road. Sergeant Feng's face was clouded with confusion. His hand shook on the wheel. Try as he might, Shan knew, in the end Sergeant Feng would not be able to avoid the truth. Chang had been trying to kill him, too.

As they finally cleared the ridge above the boron mine, Shan signaled for Feng to stop. There was a shrine he had not seen on their first visit, on a ledge three hundred feet above the valley floor. Prayer flags were fluttering around a cairn of rocks. Some were just bits of colored cloth. Others were the huge banners painted with prayers that the Tibetans called horse flags.

"I want to know about that shrine," he said to Yeshe and Feng as they parked the truck. "Find a way up there. See if you can tell who built it, and where they're coming from."

Yeshe cocked his head toward the shrine with an intense interest and began moving toward it without looking back. Feng contemplated Shan with a sour look, then shrugged, checked the ammunition in his pistol, and jogged toward Yeshe.

The mine office was nearly empty as Shan entered. The woman who served tea was asleep on a stool, leaning against the wall. Two men in muddy work clothes huddled over the large table. One offered a nod of acknowledgment as Shan approached. It was Luntok, the ragyapa engineer. The red door at the rear was closed again. There were voices behind it, and the low whir of electronic equipment.

The two men were taking measurements on one of the colorful charts he had seen before. It had a blue rectangle in the center, below rows of smaller blue-green rectangles. Suddenly Shan recognized the images.

"It's the ponds, isn't it? I have never seen such a map," he marveled. "Do you make them here?"

Luntok looked up with a grin. "Better than a map. A photograph. From the sky. From a satellite."

Shan stared dumbly. It was not that satellite photography was beyond his imagination; it was just beyond his expectations. Tibet truly existed in many different centuries at once.

"We have to know about snow melt," Luntok explained. "About river flows. About avalanches above us. About road conditions when shipments go out. Without these, we would need survey crews in the mountains every week."

Luntok pointed out the mine's lakes, the buildings of the camp, and a cluster of geometric shapes at the far left that was the outskirts of Lhadrung town. He outlined with his finger the big dike at the head of the Dragon Throat, then picked up the map and pointed to a second, earlier photo. "Here it is two weeks ago, just before construction was completed." Shan saw the spots of color that must have been pieces of equipment near the center of the brown dike.

"But how do you obtain these?"

"There is an American satellite and a French satellite. We have subscriptions. The surface of the earth is divided into sections, in a catalog. We can order up a print by section number. It gets transmitted to our console," he said, pointing his thumb toward the red door.

"But the army-" Shan began.

"There is a license," Luntok explained patiently. "Everything is legal."

A license for a Western venture to operate equipment that could survey troop movements, air exercises, and army installations as easily as it could survey snow accumulations. The Americans had worked a miracle, to obtain such a permit in Tibet.

Shan found the road leading to the mine, visible as a tiny gray line that wandered in and out of the shadows cast by the peaks. He found the road from the north, to Saskya gompa, and finally the 404th worksite. The new bridge was a narrow hyphen that intersected the serpentine grayness of the Dragon's Throat.

Shan sat beside Luntok. "I've been to the ragyapa village," he announced. The man beside Luntok tensed, and glanced at Luntok, who kept studying the maps without reacting. The man grabbed his hat and stepped out of the building.

"I spoke with Merak," Shan said. "Do you know Merak?"

"It is a small community," Luntok observed tersely.

"It must be difficult."

"There are quotas for us now. I was allowed to attend university. I have a good job."

"I meant for them. Seeing the people here and in town, but knowing most will never break away."

Luntok's eyes narrowed, but he did not look up from the photo map. "The ragyapa are proud of their work. It is a sacred trust, the only religious practice that has been allowed to continue without restriction."

"They seem well provided for. Happy children. Lots of warm clothes."