My next clear recollection is of lying on the day-bed in the sitting room. I have no memory of going down the stairs.

There was a white fuzz in my peripheral vision on the left side of my head like an out-of-focus cauliflower, an after-effect of my collision with the door. I was aware of that strange, sourceless melancholy that sometimes follows physical injury: the timor mortis of a wounded soma. Something heavy and wet lay on my head. I touched it. It was a damp dish-cloth.

‘A poultice of rasped carrots,’ Jack explained, with a certain tenderness. He gestured at me with the newspaper. ‘What means this?’

‘What does what mean?’

‘Do not push-pin with me, sir! What manner of devil are you and what hell is this?’

‘You’re staying at my house. Your sister had to go to Moscow. She asked me to look after you for a few days.’

‘To Moscow?’ His voice swooped with incredulity. ‘Lies and impudence! I have no sister!’

‘Would you sit down? You’re being rather aggressive.’

‘Aggressive? And who would not be out of countenance to be treated as I have been?’

‘Look,’ I said, ‘I’m sorry if you feel that you’ve been mistreated, but you’re a guest in this house, not a prisoner.’

My words appeared to calm him. ‘Aye, mistreated,’ he said. He gazed vacantly for a moment at the floor then thrust the newspaper at me. ‘What is the meaning of this?’

I scanned the page of headlines for a clue to his question. ‘Rail disruption this summer? Choirgirl saved by canopy in Venice hotel fall?’

‘Will you not speak the King’s English, you dog!’

‘I don’t understand your question!’ I shouted back at him, trying to match the ferocity of his exclamation.

‘This, this, what is the meaning of this!’ He was stabbing the date on the page with his finger. ‘What is twenty hundred and eight?’

‘July the twentieth 2008 is the date of that newspaper. Lucius saved it for his painting.’ As he turned his uncomprehending stare on me once more, I saw that my tendency to amplify my replies was just confusing him. ‘The date. That’s the date.’

‘By what calendar? The Hebraic?’

‘No. The normal one. Whatever it’s called. The Julian. The one that counts from the birth of Christ.’

‘’Tis not possible.’ His voice had shrunk to a disbelieving whisper.

‘Of course it is.’ I felt in my pocket for the passport that had started this trouble. ‘Look at this. It’s my son’s. See – he was born in 1995.’

Jack studied the passport closely and handed it back to me with a bewildered look. ‘Never,’ he said. ‘It is not possible. Today is not twenty hundred and eight.’

‘No,’ I said. ‘Today is twenty hundred and nine. That’s from last year.’

He gave me a look of haunted incredulity.

‘Double-check it,’ I said. ‘Look in any of those books and see when it was printed.’

Cagily, as if he were afraid to take his eyes off me, he glanced around the shelves and helped himself, one by one, to an armful of volumes. The first book he opened was my Everyman’s edition of Parade’s End. Then a couple of Arden Shakespeares and Charles Barber’s Early Modern English. After those, he went back to the shelves and took off the fifth and final volume of my 1812 edition of the works of Henry Fielding. They were a gift from my mother on my graduation and though not of major bibliographic interest, they’re some of the very few books I own that you could call antiquarian. He opened its foxed, yellowing pages; a book that was being printed the year Napoleon invaded Russia; before a single railway line had defaced the countryside; when London was a city of just over a million people, and the hot air balloon was the pinnacle of aviation, before the internal combustion engine or penicillin had ever been thought of, and yet which was to him shocking in its modernity. He studied the title page intently, running his finger over the type, until it reached the final incontrovertible date at its bottom. I remembered how I had done the same the day my poor late mother handed me the books so proudly over lunch the first and last day that she came up to Cambridge. I was full of self-love in those days and had thought ungenerously that she looked small and grey and timorous. And I remembered how I had said something conceited and ungrateful: ‘It’s a bit out of my period but it’ll look good on the shelves.’

His whole demeanour altered. He seemed to slump and grow weary. Almost in a whisper he said: ‘Nay, sir. I am deceived.’ The book slid out of his hands and flopped onto the floor. He tottered weakly to the armchair and sat down.

‘Sir, I pray you, conduct me to those that know me. I am gone out of my wits.’ He sat there, staring hopelessly at his big, sallow feet. ‘I am a gentleman, sir. If I have done you an unkindness, I will offer you redress as you think fit.’

He didn’t move. The silence stretched so long that I wondered if he’d had some kind of stroke, or shut down as he had seemed to that day in the St James’s Square mansion.

I approached his motionless bulk. From it rose an odd array of smells: musty clothes, pear drops and a vegetal scent of decay.

*

Vera had left me with two numbers: one British and one Russian mobile phone. Both diverted me to a recorded message. I called Bykov instead. I have no difficulty being assertive in English, but speaking in Russian, I feel myself quailing and diffident; a handicap made more acute by the natural brusqueness of most Russian interlocutors. Shorn of the assistance of gesture and visual clues, telephone conversations are the hardest linguistic challenge for a non-native speaker, but even given the strange density of the Russian language, our communication was so laconic as to be absurd.

Bykov picked up on the second ring. ‘I’m listening,’ he said.

I tried to explain the incidents that had taken place that morning, but I ended up sounding more hysterical than genuinely endangered. Bykov told me there was nothing to be afraid of, and he chided me for not giving Jack his medication. He made it gently but firmly plain that we had no option but to go along with Vera’s plan until her return. He could sense that I was looking for a way out, and wasn’t going to offer me one. ‘Give him the pills, Nicholas,’ were his parting words. ‘Or he will go out of his mind.’

*

The pills were in the spongebag Vera had given me. After a moment’s hesitation, I took the precautionary pepper spray as well, slipping it into the pocket of my dressing gown.

Jack was sitting quietly in my armchair in the front room, reading Volume One of my edition of the Collected Letters with the same mixture of delight and recognition that you might feel on looking over an old diary. He was so remorseful about my injury that he required no persuasion to take his medicine. His outburst over, he had the vulnerability and trustingness of a toddler.

He undressed in front of me without embarrassment. The suggestion of physical strength that he presented clothed was revealed, when he stripped, to be largely illusory. He was overweight. The fat on his legs was loose and shambling like the flesh on the hindquarters of a cow. His belly was white and awkwardly protuberant. His muscles were mostly wasted and his knees caved in slightly giving a teepee-like structure to his stance. He was wearing red Y-fronts with white piping. Most strikingly of all, the front of his left thigh bore a harsh and incongruous tattoo – a large black roundel intersected by a cross. He washed, and shaved himself with a disposable razor that Vera had packed into his bag. I glimpsed him through the bathroom door, working the lather over his face with the painstaking and clumsy slowness of a four-year-old icing a cake. For breakfast he ate a couple of bread rolls and a banana, and drank six cups of tea. He had the Ballymaloe Cookery Book open in front of him and as he chewed, he moved his eyes over its pages with the joyless and puzzled attention that he gave to everything. Outside the kitchen window, next door’s cat stalked proprietorially through the ruins of my vegetable patch.