In hindsight, I marvel at the subtlety and prescience with which Tikhomirov played his hand. I've often thought of that day on the motorway to Sheremetyevo, when he spoke of simulacra. What confused me for a long time was why, if he knew the details of the Bolshoi Theatre assassination plot in advance, as he must have done, he felt it necessary to go through the motions of using me to discover the same information. Why, if he knew what part Oxana was to play, and he must have done to have mounted the operation to fake her death, did he pretend to fall for the diversion?

That was a year ago. Today the world is a different place. Tikhomirov is president of Russia, and in Europe a new cohort of nationalist leaders has arisen, an advance guard of the new world order, all of them bearing the mark of the Twelve. Oxana and I have new identities and live in one of the outer suburbs of St. Petersburg. Our apartment is quiet, with views over a park, which is pretty in summertime and beautiful, if melancholy, in winter. Oxana is at university in the city, studying for her linguistics degree. She is a few years older than the other students, and I suspect that they find her a little strange (on the single occasion that I met her there, two of the young men on the course looked actively scared of her), but she promises me that she is making friends. I divide my time between reading, walking and working for an online translation bureau. Next year, I hope to start a distance-learning course in psychology. There's so much I want to understand.

It was only when Tikhomirov was elected president that everything made sense. The death of his forerunner, Stechkin, was not something that he had been working to prevent, but to achieve. To this end he'd played a long game. Having discovered the Twelve's assassination plan (probably through Richard Edwards, whose capacity for betrayal appears to be limitless), he'd done a deal with them. The Twelve would get their show killing and Tikhomirov, having heroically, but unsuccessfully, attempted to thwart them, would replace Stechkin as president. If Tikhomirov's failure to prevent the assassinations was to be forgiven, following the inevitable investigations, it had to be made to appear that he'd had much less information to work on than was in fact the case. My role was to be his undercover agent, but also his backstop. That's why he let Oxana live. To keep me silent. And if necessary, on message.

Should I have guessed this earlier? Should I have realized that no halfway professional sniper team would have included someone as inexperienced and as temperamentally unsuitable as myself? Probably, but I was so fixated on remaining close to Oxana that I missed it altogether. Perhaps, in the end, it's just as well.

There's much that I don't know, and probably will never know. How did the Twelve find Oxana and me in St. Petersburg? Did Dasha betray us, and if not what was the basis of her arrangement with Tikhomirov? More generally, who has the whip hand now, Tikhomirov or the Twelve? Is he their instrument, or are they his? Inevitably, images of that grotesque tableau mort in the Bolshoi's presidential anteroom quickly surfaced on the Internet. As a statement of the Twelve's power and reach, and as a warning to other world leaders, it couldn't have been more effective.

In return for the part that we played, knowingly or unknowingly, in the president's rise to power, and for our continued silence and compliance, a monthly payment is made into the bank account that Oxana and I share. The sum is not large, but it meets most of our needs. I save the money I earn from translation for foreign trips. In September we went to Paris. We stayed in a small hotel in the fifth arrondissement, ate our breakfasts in the tiny courtyard and visited the shops around St. Sulpice, where Oxana made me try on clothes we couldn't afford. We didn't go anywhere near her former apartment.

Dasha Kvariani is thriving. We met her unexpectedly on Sadovaya Ulitsa, near Oxana's university, where Dasha has opened a nightclub. We went along to the club one evening, and she gave us dinner in the VIP suite, but the conversation didn't flow and Oxana became agitated. We were all too conscious, perhaps, of the weight of each other's secrets.

Winter is here again, and in the park below our apartment the trees are bare and the fountains frozen. I am reading, and Oxana is completing an assignment on her laptop beside me. She is a very competitive student and will be expecting a top grade. Neither of us has spoken for an hour, nor felt the need to. When she finishes her work Oxana closes the laptop, reaches out and takes my hand.

We've often talked about that evening at the Bolshoi Theatre. Not so much about the events in the scarlet anteroom, but about what followed. While the theatrics might have been necessary, Oxana tells me, they were horrible. The blank cartridges, the blood pack under her shirt, all of it. What she remembers most keenly is hearing me scream. At that moment, she remembers, something shifted inside her. "I could feel what you were feeling."

This morning, we took the Metro to Nevsky Prospekt. The pavements were crowded with shoppers, their breath vaporous in the cold air. We had lunch in Café Singer, above the House of Books, then crossed the road to Zara, where I tried on skirts and sweaters and Oxana bought a hoodie. By the time we came out of the building, the brightness had gone from the sky and the first snowflakes were drifting down. Arm in arm, we walked down to the embankment. We spent a long time there, but no one took any notice of us. We were just two women gazing out over the frozen Neva river, in the fading light of a Russian winter afternoon.

Last night I awoke in the early hours of the morning, weeping. I was certain that Oxana was dead, and that the events of the last year had all been a dream. It took almost a minute of her holding me and saying my name to convince me that she was alive. She doesn't experience these terrors herself, but she sees their effect on me and knows that what I need at such moments is to know that she is real, and here.