He didn't mean mine, my death. The shadow executive doesn't necessarily expect to return from a mission; that much is a given — it's in our contract. And it is understood by all parties concerned that in inclement circumstances the life of the undersigned may become forfeit despite any or all efforts that will if possible be made to protect him.

We've lived with that one from the beginning, and never pay it much attention. People get killed in bullfights, in marital strife, on the road. What frightened me was that Pepperidge meant Xingyu's death, not mine.

'I don't want,' I told him, 'to make guesses.'

'No, quite.'

If you think I was giving him a hard time, my good friend, you are in error. I wanted to be absolutely sure of what my director in the field would give me for instructions, because in the heat of action I might forget what was said, or what was meant.

Pepperidge took a step or two, his thin body stocky-looking in his padded windbreaker, his raw, knuckly hands tucked under his arms, his eyes resting nowhere.

'Quite. Well, let me ask you this. Do you think there's any chance of persuading Dr Xingyu to carry a capsule? If you explained the need?'

I didn't even have to think about it. 'No.'

'Understandable, quite, devoted to his wife and all that. Just thought I'd ask, because you've been with him longer than I have.' He turned away, taking another step, so that his voice reached me indirectly, echoing softly off the walls above the moaning of the wind outside. 'So what it comes down to is this. I need to know whether, in order to protect the mission, you yourself would be prepared to take his life.'

He looked like a Buddha sitting there.

I didn't know if he'd seen me; he didn't give any sign.

There was a three-quarter moon outside; it had lit my way, no more than a patch of light through the haze of the flying sand but enough to show me the road, rutted by carts, up the long hill to the monastery. It shone through the oblong gaps in the walls here that once may have been windows, and through the broken timbers bracing the roof, its light leaning between the pillars, some of them rearing at an angle: the whole top floor had shifted, by the look of it, during the fire. There were ladders everywhere, most of them broken, hanging from their top rungs from the floor beams; the one I'd just climbed was the only one still usable — I'd checked for that, earlier, when we'd come here.

He sat very still, the moonlight touching on his scalp, turning his red robes to black, conjuring a spark of luminosity in the shadow of his face, a tiny jewel from this distance, his eye. So he was watching me.

This place was a catacomb, its spaces tunnelling through massive timbers, its perspectives broken by frozen cascades of plaster blackened in the fire, by doors hanging from a single hinge, with cells making hollows darker than the walls, and galleries running as far as the light allowed the eye to follow. The smell of the fire was still here, acrid in the mouth.

The wind shrieked, rising to a gust and dying again, keening, and sand drifted through the beams of moonlight as if through the timbers of a wrecked galleon. I'd made no sound coming here, climbing from the main hall of the monastery: I wanted to know how good this monk would be as Xingyu's guard; but there was enough noise going on already, from falling debris and the shifting of joists and roof beams as the wind shook the building. Perhaps he'd seen me in any case from the distance, as I'd climbed the ladder.

He hadn't moved, but since his eyes were open I knew he wasn't meditating or in prayer, but I gave a bow to make sure I wasn't disturbing him, and he returned it, getting to his feet when I neared him, a gold tooth gleaming as he greeted me with his palms touching lightly together. He was agelong, fully ordained.

'He sleeps,' he whispered to me.

'I won't disturb him. Did he ask for anything?'

'For paper, to write. And must buy drug.'

'What drug?' He couldn't mean insulin.

'For the sickness that he has.'

'For his diabetes? He needs more insulin?'

'Yes.'

'You mean there's none left?'

'Must buy tomorrow, he say.'

He could have warned me, Xingyu, for God's sake, that he was getting low.

'All right,' I said.

'Peace be with you,' the monk whispered. We exchanged bows, and he moved along the gallery, a rufous shadow in his robes, picking his way across the gapped timbers to the ladder.

He'd been upset, Xingyu, by the fuss in Hong Kong, the airport snatch and the mask and having to go back through the terminal for the flight to Chengdu; it could have made him forget he was running low on insulin. But that might be his way, to forget things, and I'd have to watch it: he could be living half his life on the edge of the galaxies, the absentminded-professor syndrome, it could be dangerous, could be dangerous now — how easy would it be to get hold of insulin in a place like Lhasa?

I opened the door of the cell as carefully as I could, but the wooden hinge still creaked. It wasn't a cell exactly, though Jiang the abbot had called it that; it had once been three or four cells, but the shifting of the building during the fire had brought down some of the flimsy plaster walls, and we had the luxury of space here, you could call it a guest room, almost, a royal suite, with glass in every window and straw on the floorboards, a pipe from a cistern on the roof bringing water to the metal trough in the corner where the midday sun thawed the ice and you turned the tap on with a wrench. It had been used, Jiang had told me, to accommodate a visiting dignitary on a secret mission for His Holiness during the 1959 rebellion; hence the glass in the windows and the water basin, and of course the unlikelihood of our ever being found here on the fifth floor of a ruined hulk.

I couldn't tell if Xingyu was awake, as I opened my sleeping bag. He didn't speak, or even stir, as far as I could tell with the noise the wind was making, and I found myself worrying, as I believe young mothers do, whether my precious charge was sleeping quietly or lying there in the silence of untimely death: the insulin thing was on my mind, and I didn't know how fast a coma could set in, with a change of diet.

I lay on my side, with dust sometimes settling on my face and making the skin itch as the wind fretted at the cracks in the ceiling, worrying also that I had crept in here to lie in the dark beside this man, his watchful guardian and defender of his faith, but if things went terribly wrong, his executioner.

So what it comes down to is this — Pepperidge — I need to know whether, in order to protect the mission, you yourself would be prepared to take this life.

I hadn't said anything.

Sand blowing across the window. Took another step, Pepperidge, head down, looking at the floor. 'Let me spell out the situation for you. Memory is fallible. The situation I'm talking about is one in which for some reason Dr Xingyu were found and seized and you were unable to save him, but were able to take his life before it was too late, before there was any time for the KCCPC to put him under interrogation. I hope that's clear.'

'Yes.'

It wasn't likely that a situation like that would come up: it was more liable to be one thing or another — either I'd succeed in protecting Xingyu and bringing him home safely to the plane for Beijing, or something would go wrong and the KCCPC would infiltrate our operation and catch Xingyu and break him and send him to Beijing for the puppet show. But I could think of a hundred situations, a thousand, where I could be right in the middle of a last-ditch action to save the protege and indeed have the option of seeing him taken away or protecting the mission by taking his life. The most obvious scenario would be that we were both found and seized and taken for interrogation, giving me the chance of seeing to Xingyu somewhere along the way and then popping my capsule. We were both replaceable, and Bamboo could survive.