'After my capture I was persuaded – willingly persuaded – by, in particular, a French colonel (whose name is best kept secret), who convinced me that by helping them, I could ultimately be helping Russia itself to become a republic as great and as powerful as France or America ever could be. I was returned to Russia as though I were a freed prisoner-of-war. In reality it was an act not of liberation, but of infiltration.

'So you see, Aleksei, for almost the whole time that I have known you, I have been a French spy, but believe me, that is the only matter on which I have deceived you. You may regard that as small consolation, if consolation at all, but in everything I have ever said to you, in every matter of opinion, of strategy and of friendship there has been no veil of pretence between us, nor between me and Vadim or Dmitry. The Maksim you have known has been the true Maksim in all aspects except this one tiny issue of allegiance. Men of different political colours and even of different nationalities do not have to be at war with each other, and even when they are they become enemies not out of choice but out of circumstance. Their friendship can be rekindled once the smoke of battle has cleared. If I had been born French then, although we might not have become the friends we once were – that I hope we still are – I would at least have retained your respect. That is not to say that I am blaming my treason on an accident of birth. I would not choose to have been born French rather than Russian. My affiliation has always been to ideas rather than to states. My hope was to take an idea born in France and see it flourish in Russia.

'Whether I have in practice been of very much use to France, I have to doubt. The only work of significance that I have undertaken has been alongside you, Vadim and Dmitry. I count my allegiance to you three higher than any and so I could never have handed over any information that would have directly put you in jeopardy. As to the more general picture of the state of our armies which I have conveyed, I doubt whether any of it has been of much assistance.

'I write this not in any attempt to exonerate myself or to make some plea for clemency that may help me avoid my execution as a traitor. I will attempt to avoid death by flight, but not by denial of what I truly believe. I write it simply in the hope that, though you may rightly condemn me in your own heart to death, you will at least regret that it had to be so.

'However, I would have no scruple that urged me to tell you the truth about myself had it not been for the fact that you most certainly already know the entire truth. It is of the circumstances of how this truth came to be revealed that I must give you every detail I can recall, in the hope that what I tell you may help in some way to defeat these despicable creatures whose war on humanity casts into unmistakable relief the petty squabbles of petty nations.'

'So he did know about them,' I said, half to myself, half to Dmitry, though I had been convinced of it almost from the start.

Dmitry did not respond. He sat with his back to the wall, almost mirroring the posture of Maks' lingering remains. The two sat at opposite corners of the same wall, like naughty schoolboys who have been told to sit apart. Neither, for very different reasons, could raise his eyes to look at me as I continued to read.

'When we returned to Moscow from Smolensk, I had had no opportunity for several months to make any report back to my superiors in the French camp. (By the by, when you see Vadim, tell him that in the French army I also carry the title of major, so he can no longer pull rank on me. To be honest, I think they bump up the ranks of agents just to flatter them. I hope that, despite what I have done to him, Vadim will be able to smile at this. I know I have no right to be flippant, but I cannot tell you how much I long for just five more minutes of the times when we used to sit beside the Moskva and drink vodka and tease one another – but mostly tease Vadim.)

'Our return out west with the Oprichniki gave me a fine opportunity to get back behind French lines and report what I knew. I looked for every chance to separate myself from Andrei, Simon and Iakov Alfeyinich, but it transpired that they were even more keen to be rid of me than I was of them. The very same night that we set out from Gzatsk – the last time, in fact, that I saw you – first one, then two, then all three of them had made some excuse to separate from the rest of the party and scout around on their own.

'I took full advantage of the solitude and headed straight off for the French encampments to the west of the town. I told them all I knew – again, I must assure you, nothing of our personal work, nor even of the Oprichniki, although on that latter point I wish I had – and after a couple of hours of debriefing I was treated to the wine, food and good company that is bestowed on any patriot who has been so long away from his confederates. It meant little to me. I seek little more from food than nourishment and the company was not as good as I have known.

'It was after sunset on the evening of the next day, as I was preparing to leave, that suddenly the camp that I was in came under a ferocious attack. Screams came from all around us in the darkness. I looked out of the tent, in which I had been talking with three other officers, to see two figures that I recognized as Andrei and Iakov Alfeyinich creeping towards the sentry who stood guard outside. I could only see the sentry's back. He could see the two Oprichniki that approached him and his head turned from one to the other in disbelief. Eventually, he fired his musket at Andrei and without doubt the musket ball passed through his chest, but hindered him no more than would a brief gust of wind. Iakov Alfeyinich dived for the soldier's legs. The soldier responded by stabbing his bayonet hard down into Iakov Alfeyinich's back. It was as ineffective as the musket ball had been.

'Iakov Alfeyinich's attack brought the sentry to the ground and in the same instant that he fell, Andrei launched himself upon his throat. What I saw then is beyond any comprehension of a civilized man. My upbringing never allowed any of the myth and folklore that is the staple for so many of my contemporaries. From what little I heard in the schoolyard of vampires and werewolves and other such abominations, I was glad to have been spared such nonsense. Even those who did hear those stories as children do not grow up to believe them. But any man must believe the evidence of his own eyes.

'Andrei sunk his teeth deep into the man's throat and tore off a sliver of flesh. The soldier was still alive and struggling for freedom beneath Andrei's firm grasp as Iakov Alfeyinich fell upon him and took a similar bite from the other side of his neck. Then the two lay there beside him, their mouths to his neck, lapping away at the blood that seeped out of him. It was only when the sentry had ceased to breathe that the two Oprichniki raised their heads from his throat and exchanged between themselves a glance of pride and self-satisfaction.

'Before they could rise, three more soldiers were upon them. Again, the damage inflicted by shot and by blade had little impact. They killed by the same method – with their teeth – but now they did not linger to drink the blood of their victims. Time had become too pressing for them to enjoy the aftermath of the kill.

'I turned back to speak to the other officers in the tent with me and was horrified by what I saw. Two of them lay dead upon the floor. The third remained upright, showing on his contorted face a look of agony that was matched only by the terror revealed in his staring eyes. Over his shoulder I saw the face of Simon, looking down to where his teeth were sunk into the man's neck. Behind his teeth, Simon's tongue flicked back and forth between the man's sinews, to taste every drop of blood he could find, much as a dog's tongue probes every crevice of his bone in search of the last tasty morsel of marrow.