'Useful, I suppose, for cutting your chest open when you create another one of you.'

'Then, and at other times.' He was more reticent on this matter than he had been on others. Another question raised itself in my mind, and the image of my own hand driving a stake into a young woman's chest.

'Did I need to kill Margarita?' I asked. 'Was she dead when we found her, or had you made her… one of you?'

'She was dead,' he said calmly, his eyes fixed on mine. 'I killed her.'

'But why? Why waste the chance of turning her into a vampire?'

'I killed her because I enjoy it. But as to turning anyone into a vampire, I am sadly incapable of that.'

'And why is that? I'm sure you must far outstrip the others in your ability to persuade people to willingly take the step.' I didn't like to compliment him, but as I had long ago discovered, he was the only one of the Oprichniki who showed any real personality.

'Certainly – and that, for me, is one of the most pleasurable parts. The problem, though, is a physical one.'

'What do you mean?'

'As we have discussed before, I am not a doctor. I cannot explain how these things work. I can go through the motions but it simply does not happen, any more than it would if you were to attempt it.'

'Except that I wouldn't even want to attempt it,' I added vehemently.

'That may be the difference between us,' he smiled.

'So in the end, despite what you both did, despite her willingness, Margarita did not become a vampire. When you killed her she died as a mortal human.'

He nodded thoughtfully and then looked towards me with an intent gaze, pinching his bottom lip between his fingers, indifferent to the inconvenience of his bound hands. I was reminded of the discussion of chess he had introduced earlier. He was a player who had made a move and was now trying to determine whether I, his opponent, had seen the full ramifications of it.

'What were you doing when you were captured?' I asked.

'Spying for the French.'

'Really?' I laughed.

'Really. I need to leave Russia. They are leaving Russia, or at least trying to. I can help them while our interests coincide.'

'It can't help you or them much for you to be captured. I presume that wasn't part of the plan.'

'No, you're right, it wasn't. Not until I happened to see you trotting down the road towards the camp. Then I knew I just had to see you one more time.'

So – assuming that he was telling the truth – he had not been following me. It had simply been luck that we had found each other again, though a luck that we had both been trying to manufacture. That he had not been following me made it all the more likely that he did not yet know about the death of Foma. I felt sure now that there was no escape for him.

'One more time before you died,' I added.

'One more time before I left your country,' he countered. 'Being the only one of us left, I feel it my duty.'

'The only one left?'

'Well, you've told me about Pyetr and Iakov Zevedayinich, and I presume that Dmitry has killed Foma by now.'

I nodded. 'Foma's dead.' I was deflated, but I had to hide it. If Foma was not part of Iuda's escape plan, then what was? I recalled the possibility that he might have some human collaborator. If he did, and he was a Russian, then the man would have had little trouble infiltrating this camp. Was that the basis of Iuda's confidence, or was it mere bluff? He glanced at the two guards, some way away on either side of him, as if judging how far he could run before they could catch him.

'Dmitry Fetyukovich proved to be a startlingly brave man,' Iuda continued. 'To kill a vampire is one thing, but to take one alive is quite another.'

'You saw it happen?'

'Oh yes.'

'And you did nothing to help Foma?'

'Why should I? It wasn't worth risking my life. Dmitry believed that I would come and rescue Foma, but he really didn't understand. As I said to you, even a vampire would not risk his life to save another vampire. I take it, then, that you've seen Dmitry. Is he here with you?'

'No, he's not here,' I replied. 'Just tell me, Iuda. How do you plan to escape?'

He deliberately misinterpreted the question. 'Well, as far as I understand it, Napoleon's move to the south is a feint. Already Tchitchagov has set out to follow him on the far bank of the Berezina, and Kutuzov will soon be heading that way too.'

Although it wasn't what I had been trying to find out, it was vital information nonetheless. I followed the line that Iuda had begun. 'Whereas Bonaparte's real plan is what?' I asked.

'Ah!' said Iuda with a smile. 'See how the wily interrogator tricks his quarry into revealing all!' He leaned forward and winked with an air of conspiracy. 'Between you and me, Lyosha, he's found a ford, upstream at a place called Studienka. It'll still need bridging of course, but it should get them across.'

'Get him across,' I responded cynically.

'How do you mean?'

'There's not much of the Grande Armée left compared with what came. Thirty thousand out of half a million? It's about the emperor, not the army now.'

'And why not? Napoleon is a great man.'

'You think so?'

'He makes my life a lot easier.'

'So Dmitry was quite wrong. You were never on our side?' I asked, feeling more vindicated than shocked by the proposition.

'Not at all. If Napoleon had defeated Russia it would have meant French hegemony over the whole of Europe. And that would have meant peace – a peace you and I would have despised for different reasons, but nonetheless inimical to both of our lifestyles. True, there would still be war with Britain, but I've never been much use at sea.'

'So you just always support the underdog?'

'I like to help maintain the balance of power.'

'So now you switch sides to France when she is weak?'

'Exactly.'

'How long have you been doing this?' I asked with genuine curiosity. 'How many times have you switched sides? How many wars have you tried to perpetuate for your own ends?' I was prevaricating unnecessarily. 'What I mean is, Iuda, when did you become a vampire?'

'An interesting question,' he replied, but one which he was not going to answer.

I had not noticed it begin, but as our conversation paused, I heard that the few birds which for some reason chose to remain in the trees during the winter months had begun their daily song.

The pre-dawn dark blue of the sky was only just becoming visible, but already they had noticed it and reacted to it. I felt a little sorry. There was so much more that I wanted to ask of Iuda and discover from him, but I could not afford to be sentimental. I could so easily learn to regret any opportunity for survival that I might offer him.

'Might I be allowed to smoke?' he asked politely.

I could see no harm in it. I shouted to the guard, 'Have you got a pipe? Or a cigar?' He came over and handed me a cigar. It was a thin, withered offering – much like the man who offered it – made à l'Espagnole, with just paper to wrap it. It was possibly all he had. I gave a coin in exchange, paying – in my sympathy for his instinctive willingness to hand over even his personal possessions at a senior officer's behest – a similar price to that I would have received during my days as a tobacco vendor in occupied Moscow.

Again Iuda eyed the guard, looking for a chance to flee. I lit the cigar from the fire and offered it to Iuda. He gestured to me with his bound hands and gave an expression of humble entreaty. I placed the cigar between my lips and then cut his hands free with his own knife, before handing the cigar to him. His feet were still tied, and I had the guards with me. Besides, it would soon be dawn and Iuda would be no more threat to anyone. I felt safe.

'Thank you,' he said, inhaling deeply. I sat back down and threw the knife once again into the snow between my feet. Knowing that time was short, I searched my brain for any other questions I could put to him. One immediately occurred to me.