One emperor. Jack was barely breathing now. Not Genghis Khan. An emperor far greater than that. An emperor of all that is known under heaven.

Shihuangdi. The First Emperor.

Jack remembered the Sogdian, the man whose act more than two thousand years before had led them to this place, a man whose very existence was part surmise, part reality. Had they been right about him? Had he really stolen the celestial jewel from under the noses of the tiger warriors at Xian? Or had he been fulfilling a promise, one the first caretaker had made to the dying emperor, to take the jewel from Xian to this place, the real tomb? Had the emperor lost trust in the tiger warriors? Had he foreseen the future, seen how his legacy would be usurped by those who would profess to protect it? Had the brotherhood of the tiger been living a lie, propped up by murder, a fantasy of guardianship that had only ever been about their own greed and power?

Jack thought of the celestial jewel, the elusive treasure that had brought them on this extraordinary journey. Had the jewel been installed above the empty casket under Mount Li, a priceless heart of the emperor's dream they would be sworn to protect, yet which one day a descendant of the caretaker would spirit away and try to take to its rightful place? Jack remembered Katya's uncle, the story of the tiger warriors told by Katya herself, streams of knowledge that seemed to come from some reservoir deep in the past, exactingly remembered, pa.s.sed down from generation to generation. Jack thought of Katya again. Had there been one among the Brotherhood, one entrusted by Shihuangdi, he who trusted so few, to keep the eyes of the others away from the truth? Had they lived a lie for sixty-six generations, protecting a tomb at Xian that one among them always knew was empty? Had Katya's uncle been after the jewel not just to keep it from Shang Yong, but to bring it secretly here? Jack thought of something Katya had said about her uncle. He was grooming me. Had she told them the whole story? Who was the caretaker of the tomb now?

His intercom crackled. "Jack. Can you hear me?"

"Loud and clear."

"I've been shouting myself hoa.r.s.e. You need a ten minute decompression stop. The surge might have pressurized the water and put you beyond your no-stop time."

"Five minutes at twenty meters, five at ten."

"Roger that."

"The intercom interference must have been electromagnetic."

"I've been worried about that. The quake might have dislodged that lost torpedo, and reactivated something in the electronics."

"We'll want to cordon off the area," Jack said. "This whole sector of coast becomes a no-go zone. That's our condition for working with NATO and the Russians. We'll fund the whole cleanup operation, put the Russians through any underwater training program they want. Once everything's ready, two years, maybe three years down the line, we'll initiate the search. n.o.body goes in the water before then. Health and safety."

"Right, Jack. As if health and safety's ever been high on your list. So what exactly did you find down there? I take it we're looking at more than a bronze mirror."

"Is this a secure channel?"

"A closed system. Just you and me. The navy boat didn't have the right receiver and we couldn't get one freighted out in time."

Jack cleared his throat. "I found a statue and some bones."

"I said, what did you find, Jack?"

"That's what I saw for certain. That's what I touched."

"Right."

"Okay, I might have found a tomb."

"Genghis Khan?"

"Not sure. We need more to go on."

"You didn't find the jewel? The other one. The peridot."

"I didn't find the jewel. But it may be the right place. If Fabius and the others did reach the eastern sh.o.r.e of the lake and then went down in a storm, this is about where the wreck would have ended up. Everything they carried with them might still be here, somewhere in the silt below us now. Or Fabius may have escaped and taken it with him, into China toward Xian."

"Back toward the First Emperor's tomb."

"To the place that history calls the First Emperor's tomb."

There was a brief silence. "Are you saying what I think you're saying?"

"I only saw it for a second. Less than a second. But I'm sure of it."

Costas checked the old Rolex diving watch he wore over his suit and gave a thumbs-up. Jack repeated the gesture, and watched the depth gauge inside his helmet as they rose ten meters. Their buoyancy systems automatically adjusted to neutral and Costas turned to face Jack. "So, how are you going to explain to your daughter that she's been responsible for one of the greatest archaeological discoveries ever made, something that could change the perception of Asian history, but that we're going to say nothing about it and instead talk about a torpedo, or if pressed maybe mumble something about Genghis Khan?"

"I don't want to tell anyone. For the reason you just said. Asian history. There's too much at stake. A whole national myth. Right now, the Chinese might need that myth, the myth of the First Emperor's tomb at Xian, the myth of untold wealth buried with their greatest ruler. Revealing the truth might unleash a dangerous unfolding of control in China."

"You don't believe that. I've never known you to leave treasure unexcavated because you're worried about a national myth."

"Okay, I just want to wait until the seismic activity quiets down. That can take a couple of years out here. And that should give us time to develop equipment for getting through a mountain of lake sediment. Give you time, I should say."

"I was blueprinting a new sub-bottom excavator in my mind while you were ferreting around down there. I knew you'd got something, and that we'd be back. So what about Rebecca?"

"Two, maybe three years down the line. When we're ready to come back here. Then I'll tell her what I saw. I'd rather her first big discovery wasn't one that might upset the entire world order."

"Kids know everything. She'll be onto you as soon as she sees that look in your eyes. And show me one of our discoveries that didn't upset the course of history. If she sticks around, she's going to have to get used to that. She'll be up there on the boat by now," Costas added. "I bet you tell her, the moment we surface."

Jack looked up. They had only a few minutes now. He tasted a hint of salt from the lake. He remembered something Katya had told him, an old Kyrgyz legend about how the nomads kept the spirits of their ancestors at bay by weeping into the lake, along the sh.o.r.eline beside the carved stones that marked their pa.s.sing. If the mourners wept, the waters would rise around the ghosts, and they would drown. But now there were too few mourners, too few left to remember. Jack had seen the boulders left dry by the receding sh.o.r.eline, the stain of a watermark meters above. Now the mountains themselves needed to mourn, to release melt.w.a.ter in torrents, to keep the spirit below them at bay, the spirit of Shihuangdi, the First Emperor.

Jack thought about where they were again, the fabled Silk Road. A place swept by the divine wind, where little is left except myth and legend, stories that still adhere only because they are so light and insubstantial.

But not here. Not underwater. This was real.

There was another tremor, more violent this time, and a darkness swept over the lakebed below them, obscuring it completely. Jack checked his computer. It was time to go. Costas jerked his thumb upward. Jack looked up, and saw the shadow of the patrol boat, and moored beside it the Zodiac, its outboard directly overhead. A cl.u.s.ter of faces was visible over the stern of the patrol boat, around the ladder where Costas was already beginning to ascend, but a solitary face was peering down at him over the side of the Zodiac. The hulls were like dark clouds, but the faces reflected off the silvery surface of the water like stars, the brightest one directly above him. Jack rose up and broke surface, then flipped up the visor from his helmet and held on to the side of the Zodiac, looking up at the face with sungla.s.ses and long dark hair gazing down at him. He kicked up and peered over the top of the pontoon, seeing that they were out of earshot of the others. He dropped down again and gestured for Rebecca to come closer. He snorted into the water and cleared his throat. He was as excited as he had ever been in his life.

"You remember our trip to the terracotta warriors exhibit in London?" he said. "Well, you are not going to believe what we've just found."

"Try me, Dad."

Gansu Province, China Forty-eight hours later, Jack stood in front of a low wall, the remains of a rampart that had once been several meters thick inside a complex of ancient ruins. He knelt down and touched the surface, feeling it crumble in his fingers. It was loam, compacted clay with fragments of pink and gray granite. This place desperately needed rain, but the wall was so desiccated that rain would only hasten its destruction, washing it away rather than strengthening it. The loam looked like ancient concrete, like mortar, but was not. This wall was not Roman. He turned and waved to Costas, who was trudging up the path behind him, a slightly disconsolate figure in the dust. Farther back he could see Katya and Rebecca, picking their way together among the stones, and beyond them a dust cloud where the rotor of the Lynx helicopter was powering down. The helicopter had flown them here in stages from Lake Issyk-Kul in Kyrgyzstan, east over the mountain pa.s.s of the Tien Shan, skirting the northern fringes of the Taklamakan Desert, then down the narrowing funnel of the Gansu Corridor into the heart of the ancient Chinese empire. It had been a marvelous journey, following the Silk Road from the air, and they had camped on the site of a long-abandoned caravanserai. That morning they had swept in low over the Great Wall of China, over a section constructed during the Han dynasty two thousand years ago. They were within a few hours of Xian, the eastern anchor of the Silk Road and the site of the First Emperor's tomb. But for Jack the end of their quest was this place, the last hint of an extraordinary ancient journey they had been following from another world unimaginably far to the west.

A waft of breeze brought a hint of something exotic, heady even, some crop in the valley perhaps, but then the air was still, and all Jack could sense was the dusty smell of decay and dereliction, the familiar lifeblood of the archaeologist. He breathed it in, relishing it. He wished Maurice Hiebermeyer was with him now. He would have helped Jack to make sense of the walls, the jumble of ruins. Or perhaps it was too far gone to unravel, and there was nothing more to glean than what he could see in front of him.

Jack looked around. The place had a desolate beauty. They had pa.s.sed ruinous houses, mud-brick walls bleached white by the sun, surrounded by patches of corn and barley that seemed doomed to lose the battle against the scorching sun. Rutted tracks led across stony fields, the scars of plowing and long-dry irrigation channels baked hard by the sun. In the distance the odd goat and sheep picked at the ground, finding something in the gravel and dust. The sky itself seemed scorched, colorless, and most of the time he could see nothing beyond the low plateau he stood upon, but then some upper wind would push apart the dust and the sky would streak with red. In those moments he saw the foothills of the Xaipan Mountains, great folds and spurs that rose up to a jagged skyline. To the north was another line of mountains, more distant, and between the two chains of mountains lay the Gansu Corridor, the eastern Silk Road. Here the pounding progress of the camel caravans had once stirred up a continuous storm of dust, a storm whose residue seemed to remain above the valley floor like the exhaust of history, a great exhalation from the past that was still unable to settle.

Jack realized that he had been to places like this before, on the edge of the Atlas Mountains in Morocco, in the north Syrian desert, in Andalusia in Spain. Places where ancient communities had once thrived on the periphery, but where exhaustion of the land and the spirit had overwhelmed all attempts to carve an existence out of the precious pockets of soil, so easily swept away by the whims of climate and erosion. He was told that it rained less and less here now, and the agriculture that had once sustained the village was being blown away in the wind. Soon, even the ancient walls would become part of the dust cloud that eddied and flowed along the Silk Road, caught between the endless chain of mountains that defined the corridor that had once linked the great empires of east and west.

Jack sat down on a stone revetment. Costas came up and sat beside him, wiping the dust from his face. He stared glumly at the wall. "This is when you know you're in the presence of a real archaeologist," he said. "One of the greatest wonders of history lies just over the horizon, the fabled tomb of the First Emperor, the terracotta army. But no, we come to sit in front of a crumbled wall in a wasteland in the choking dust and the burning heat. Hungry, thirsty, tired and needing a holiday very badly."

Jack pa.s.sed him his water bottle. "But I can never make sense of it without you. Archaeology, I mean. You keep my feet on the ground."

"Right." Costas swigged from the bottle, then pa.s.sed it back. "So what's the truth about this place, Jack? Is this what you brought us all the way to see?"

Jack pa.s.sed Costas a piece of paper. "I printed this out from the helicopter's computer this morning. I knew you'd need an antidote to a ruined wall. Headline news, CNN. Your elephant ship off Egypt. Remember? I think that stands up to the terracotta warriors, don't you? And we found it."

Costas peered at the photo and his eyes lit up. "Look, they got my new submersible in the picture, the ROV-6. I asked the IMU film team to get that into the publicity shots. You can even see the new strobe array. Perfect."

"The elephants, Costas, the elephants."

"Yeah, that too." They stared for a moment at the extraordinary image they had first seen ten days before, the coral-encrusted shape of an elephant sitting on the bottom of the Red Sea. Costas read out the caption. "Egyptologist Dr. Maurice Hiebermeyer announces sensational shipwreck find." He slapped the paper. "I don't believe it. No mention of us anywhere. Just Hiebermeyer."

"We've got to allow the dirt archaeologist a moment of glory," Jack said. "After all, he was the one who got us out to Egypt in the first place."

"This happened when we found Atlantis," Costas grumbled. "I'd set up a special demonstration of the Advanced Deep Sea Anthropod. The press were all over Hiebermeyer and his wretched mummies."

"That's Egyptology for you."

"Anyway, it should be you doing the interviews."

"Maurice is better at it than me. He's got all that bubbly energy. And he's less threatening."

"Threatening?" Costas peered at him. "Let me guess. You don't want the world to know there's a real Indiana Jones around, do you? It might put the bad guys on their guard. You like to keep a low profile."

"Exactly."

"You didn't answer my question. The truth about this place."

Jack gestured at the crumbling wall. "It's what you see in front of you. A few years ago, Chinese archaeologists identified these walls as Han dynasty, contemporary with the Roman Empire. They thought this might be the site of Lijian, a settlement in the Gansu Corridor mentioned in Han records. Lijian might derive from a Han Chinese word for westerner, for those who lived beyond the Persians. Later this place might have been renamed Jielu, possibly meaning 'captives from the storming of a town.' It was common for the Han to settle their prisoners of war in places that were then named after their origin. The big leap of imagination was to connect this place with the theory that the Chinese employed Roman mercenaries, survivors of Cra.s.sus' legions who had escaped from Persian imprisonment."

"So that's it," Costas murmured. "That's why we're here."

"It's not clear-cut," Jack said. "The story of Fabius and the others in the boat might have ended on Lake Issyk-Kul. But it might not. There's another possibility. A really fascinating one."

"Go on."

"The Roman survivors of Carrhae were imprisoned in Merv in 53 BC. Licinius and Fabius and their comrades made their break about thirty years later. Over the years others must have tried to escape. Perhaps one group was successful, and word filtered back to Merv of the opportunities for mercenaries in the east, the great riches to be had. Perhaps that was what inspired Licinius and Fabius. And the hints about this place would seem to refer to an earlier group. The History of the Former Han Dynasty records soldiers fighting in 36 BC for a renegade Hun warlord, deploying in a formation reminiscent of the Roman testudo maneuver with interlocked shields above their heads. That's the one shred of evidence on which the whole theory hangs. A few who had been persuaded by the argument began to identify Lijian with the Roman settlement. And here we are."

"Any Roman artifacts?" Costas said, kicking the dust. They looked up as the two women joined them. Rebecca carried on, walking around the ruins in front of them, examining the walls. Costas shifted to make s.p.a.ce for Katya on the wall.

Jack shook his head. "It's like Katya said at the Roman burial beside Lake Issyk-Kul. You wouldn't expect to find any. If Romans were here, they would have had nothing of their former life with them. It would have been stripped away from them on the battlefield, and then at Merv. But there's one fascinating feature of this place. Not artifacts or ruins, but people. There's a striking incidence of fair features, green eyes, flaxen hair, big noses. Some Chinese scholars who came here saw these features as western Asiatic, then someone remembered the Roman connection, and the idea caught on."

"What do they know about it?" Costas asked. "The local people, I mean?"

"It's impossible to tell. There might be some residual memory of their ancestry. But they're desperately poor, and buying into the Roman theory might be a ticket to tourist dollars."

Katya spoke. "Anywhere along the Silk Route you could have genetic input from the west - Persian, Sogdian, Bactrian, Indian and yes, Greek and Roman - but with input going as far back as the early Neolithic, even to Indo-Europeans who came this far. You just couldn't be certain."

Jack nodded. "DNA studies have been carried out and are pretty inconclusive. And the whole idea's based on a Chinese misapprehension about the Romans, that they were blue-eyed, blond-haired giants. Ironically, Roman legionaries from the heartland of Italy would have had more in common with the physiognomy of Han Chinese warriors - short, stocky, dark-haired, brown-eyed. What the Chinese were imagining is much closer to the Celtic or Nordic type. Of course, by the time of Julius Caesar and Cra.s.sus, there were plenty of men like that in the legions, Celts from northern Italy, Gauls, even Britons. The Huns weren't the only ones to employ mercenaries in their armies."

"What's your gut instinct?" Costas said.

Jack pursed his lips. In the distance he could see a farmer hacking at the ground, his implement bouncing off the rock-hard surface. Beyond him the mountains rose like crumpled paper, the folds and valleys in dark shadow. "My gut instinct," he replied. "This place would have been more fertile in antiquity, a more viable agricultural settlement, but always demanding, not a place of choice. My gut instinct is that prisoners of war could have been settled here."

Rebecca came over and stood in front of them. She had stripped off her fleece to reveal a gray T-shirt with the letters USMC stenciled across the front.

"You seem to have made some new friends," Jack said.

Costas inspected the shirt, nodding his approval. "Hoo-ah," he said.

"Hoo-ah," Rebecca replied, high-fiving him. Jack rolled his eyes. She flopped down on the low wall beside him and took off her cap, wiping her forehead. "It's deuced hot," she said.

Jack turned to her in astonishment. "What did you just say?"

"I said it's deuced hot." She looked at him sheepishly. "That's what John Howard would have said. I read it in a letter you have he wrote to his wife, from the jungle. When their little boy was ill. It was one of his favorite expressions. I've been thinking about him a lot. He so much wanted to be with them, but couldn't. I hope he found them in the end."

Jack put his arm around her and smiled. He remembered the lapis lazuli mine, the body. For a moment he saw them, Howard and Wauchope, standing together, not old men in ragged sheepskins but young officers, in white helmets and khaki tunics with telescopes and maps, staring off toward the horizon. He held Rebecca tight and then took his arm away. "You've just been on the cellphone to Bishkek, haven't you? How's Pradesh?"

"He's good." Rebecca suddenly looked downcast. "Altamaty and I went to see him at the U.S. medical complex at Bishkek just before we flew out here. The bullet missed everything vital. But without the first aid he would have bled to death. He's grateful to you for saving his life."

"Costas did the triage. And I hardly saved him. I was the one who put him in danger."

"The army doctor said that if it had been an explosive bullet or a fifty-caliber Browning round, he'd have been dead on impact. He said that when the bullet hit Pradesh it was subsonic and must have been fired from an incredible distance, apparently from an old rifle. It was only one inch from the heart. He'd never seen anything like it."

"And he'll never see it again," Costas murmured.

"How's his archaeology reading getting on?" Jack said.

"He's lapping it up. He wants more. He said he was already seeing the Roman finds from Arikamedu in a new way, as evidence of trade, society, beliefs, Roman, Egyptian, Indian, his own history. He's itching to get back there."

"That's what I like to hear," Jack murmured.

"And Altamaty?" Jack glanced at Katya.

"He's staying with Pradesh until they fly him out. Pradesh is trying to teach him English. They get on like a house on fire. Altamaty even brought him a doggie bag of mutton stew. He says it'll cure anything."

Costas cleared his throat. "Well, Jack. Maybe you'd like to join them. Maybe you'd like to eat some more sheep's lip."

Rebecca looked incredulous. "What?"

"It's true," Costas said. "In Kyrgyzstan, when we first met Altamaty. He ate sheep's lip. Your dad ate sheep's lip."

"Oh my G.o.d."

"I had to," Jack protested. "If I hadn't, it would have been deeply offensive. Altamaty would never have spoken to me again."

"I thought you hated mutton."

"It's the only food I can't eat."

"Couldn't you have chosen some other bit? Did it have to be, like, lip?"

"I had no choice." He eyed Katya despairingly. "It had to be lip."

"I have got," Rebecca said quietly, "the grossest dad. Ever."

Jack grinned. "We need to show Pradesh and Altamaty the ropes. A crash course at the IMU campus, and some onboard experience with our research vessels. I need to talk to the commandant of the Madras Engineering Group to arrange a secondment. Pradesh'll need recuperation leave anyway and the campus in Cornwall is perfect. As for Altamaty, his training can be part of our funding for the underwater work at Issyk-Kul and the petroglyph research project. We can put temporary staff there while he's away."