“Try harder. Or we can get a lie detector test. Yes, on second thought, let’s do that. I can probably have you back here by midnight or so.”

“Impossible!” the conductor protested. “I must ready the train for the return! We have a very tight schedule.”

“Perhaps you can make the return train tomorrow or the next day. Should I go find your boss and tell him the news? It would seem the courteous thing to do.”

“I don’t know her name!”

“Look it up. I can tell you the seat number. Right beside Sun Lunshi, the man who died.”

“I can’t look it up. She never bought a ticket.”

Shan saw how the conductor nervously watched a Public Security patrol walking down the platform. “Surely you don’t allow stowaways, even beautiful ones.”

“Surely we don’t say no to Public Security.” The conductor closed his eyes and shook his head. “Look, she ran into the station in Golmud and demanded we hold the train. She made me search my computer for Sun Lunshi and asked his seat number, then just darted on board.”

“And they stayed together the entire trip?”

“She read a magazine at first, and took a nap, or at least seemed to. I remember because it seemed odd that she seemed to have urgent business with the man but didn’t speak to him right away.”

She was working hard at doing nothing, Shan knew. It was a technique taught at police academies for not spooking informers. Show no aggressive attention, just be disinterested and casual, giving the target a chance to speak first. “But eventually they spoke.”

“I wasn’t there the entire time, but yes, about halfway through the trip. A lot of passengers were asleep by then but those two began talking.”

“Did they eat together?”

“Is that important? No idea.” The conductor took off his hat and ran his hand over his thinning hair as he tried to recollect. “Yes, something from the snack bar. Sandwiches and sodas, I think. The dining car was all booked, blocked out by tour groups.”

“You didn’t notice he was missing later?”

The conductor shrugged. “We dim the lights. People huddle down in their seats and sleep.”

“And she never asked you about him, never acted as though she might be concerned about his whereabouts when he disappeared?”

The conductor hesitated as he grasped Shan’s question. “No,” came his nervous response.

“As if she did not expect him to return.”

The conductor’s face clouded. “I’m not the detective here.” He retreated a step then paused. “She looked in his baggage when he left. The overnight bag and the tube.”

“Tube?”

“A long black tube with a handle on it, nearly as long as your arm. One of those cases used for charts and blueprints.”

“And maps,” Shan suggested. “It was not with the baggage collected after he died.”

“Because she took it.”

“And you didn’t stop her?”