He opened his notepad. They were still there, on the last page. His father's name. His name. Without thinking he drew another character, a complex figure, beginning with a cross with small slashes in each quarter pointing to the center. Thrashed rice, these first lines meant. They connected to the pictograph of a living plant over an alchemist's stove. Together they meant life force. It had been one of his father's favorite ideograms. He had drawn it in the dust of the window the day they came to take away his books. Choje had taught him its counterpart in Tibetan characters. But Choje always referred to it differently: the Indomitable Power of Being.

There was a movement in front of the desk. He slammed the notebook shut, his hands reflexively covering it. It was only Feng, standing as Lieutenant Chang approached.

Chang pointed at Shan and laughed, then leaned toward Feng and spoke in a low voice. Shan stared past them out into the office, watching the monochromatic figures move through their paces.

Opening the pad again, he remembered Passage Twenty-one of the Tao Te Ching and wrote it at the end of his investigation notes. At the center is the life force, it said. At the center of the life force is truth.

He propped the pad upright in front of him, open to the verse, and studied it. Every case has its own life force, he had once told his own deputies, its essence, its ultimate motive. Find that life force and find the truth. At the center there was a murdered prosecutor. Shan tilted his head and stared intensely at the verse. Or perhaps at the center was the 404th and a Buddhist demon.

He became aware of a small noise in front of him. "What are you doing?" Yeshe asked with a self-conscious glance back at Sergeant Feng. "I've been standing here for five minutes." He was holding a plate with three large momo dumplings. Beyond him, the office outside was empty. It was dark.

The momos were the only food Shan had seen all day. He waited until Feng turned his back and stuffed two into his pocket, then gulped down the third. It was rich, with real meat inside, prepared by the guards' kitchen. In the prisoners' mess the momos were stuffed with coarse grain, with a heavy portion of barley chaff always mixed in. His first winter, after drought had shriveled the fields, the momos had been filled with the ground corncobs used to feed pigs. Over a dozen monks had died of dysentery and malnutrition. The Tibetans had a word for such deaths by starvation, which had claimed thousands in the days when almost the entire monastic population of Tibet had been imprisoned. Killed by the momo gun. After the drought the Tibetan Friends Association, a Buddhist charity, had won the right to provide meals twice a week to the prisoners. Warden Zhong had announced it as a gesture of conciliation, and done so so cheerfully that Shan was confident that the warden was pocketing the money that would have otherwise fed the prisoners.

"I have compiled notes of our interview with Dr. Sung," Yeshe said stiffly, and pushed two pages of typed text across the desk.

"That's all you have been doing?"

Yeshe shrugged. "They're still working on the supply records. They had trouble with the computers."

"The lost supplies you mentioned?"

Yeshe nodded.

Shan considered the notes and looked up absently. "What kind of lost supplies?"

"A truck of clothing. Another of food. Some construction materials. Probably just some bad paperwork. Somebody counted too many trucks when they left the depot in Lhasa."

Shan paused to make a note in his book.

"But it's nothing to do with this," Yeshe protested.

"Do you know that?" Shan asked. "Most of my career in Beijing I spent on corruption cases. When it involved the army, I always went to the central supply accounts first, because they were so reliable. When they counted trucks, or missiles, or beans, they didn't do it with one man. They assigned ten, each counting the same thing."

Yeshe shrugged. "Now they use computers. I came for my next assignment."

Shan considered Yeshe. He wasn't much older than his own son, and, like his son, was so smart, and so wasted. "We need to reconstruct Jao's activities. At least the last few hours."

"You mean talk to his family?"

"Didn't have any. What I mean is, we need to visit the Mongolian restaurant in town where he had dinner that night. His house. His office, if they let us."

Yeshe had his own notepad now. He feverishly took notes as Shan spoke, then spun about like a soldier on drill and departed.

Shan worked another hour, studying the lists of names, writing questions and possible answers in his pad, each seeming more elusive than the last. Where was Jao's car? Who wanted the prosecutor dead? Why, he considered with a shudder, did Choje seem so perfectly assured that the demon existed? How is it that the prosecutor of Lhadrung County had appeared to be a tourist? Because he was preparing to travel? No. Because he had American dollars in his pocket, and an American business card. What kind of rage did this killer possess, to carefully lure his victim so far just to decapitate him? Not an instantaneous animal rage. Or was it? Could it have been a meeting turned sour, escalating to a fight? Jao was knocked unconscious and in a panic his assailant picked up- what, a shovel?- to finish the job and destroy Jao's identity in a single grisly act. But to then carry the head five miles to the skull shrine? Wearing a costume? That was not animal rage. That was a zealot, someone who burned with a cause. But what cause? Political? Or was it passion? Or had it been an act of homage, to lay Prosecutor Jao in such a holy place? An act of rage. An act of homage. Shan threw his pencil down in frustration and moved to the door. "I have to go back. To my hut," he told Sergeant Feng.

"Like hell," Feng shot back.

"So you and I, Sergeant, we are going to spend the night here?"

"No one said anything. We don't go to Jade Spring until tomorrow."

"No one said anything because I am a prisoner who sleeps in his hut and you are a guard who sleeps in his barracks."

Feng shifted uneasily from foot to foot. His round face seemed to squeeze together as he gazed toward the row of windows on the far wall, as though hoping to catch an officer walking by.

"I can sleep here, on the floor," Shan said. "But you. Are you going to stay awake all night? That's what you would need orders for. Without orders the routine must stand."

Shan produced one of the momos he had saved and extended it to Feng.

"You can't bribe me with food," the sergeant grunted, eyeing the momo with obvious interest.

"Not a bribe. We're a team. I want you in a good mood tomorrow. And well nourished. We're going for a ride in the mountains."

Feng accepted the dumpling and began to consume it in small, tentative nibbles.

Outside, the compound was gripped in a deathly silence. The crisp, chill air was still. The forlorn cry of a solitary nighthawk came from overhead.

They stopped at the gate, Feng still uncertain. From the rock face came the echo of a tiny ringing, a distant clinking of metal on metal. They listened for a moment and heard another sound; a low metallic rumbling. Feng recognized it first. He pushed Shan through the gate, locked it, and began running toward the barracks. The next stage of the 404th's punishment was about to begin.

Shan offered the remaining momo to Choje.

The lama smiled. "You are working harder than the rest of us. You need your food."