Having a near-eidetic memory means two things. Predominantly, it means nearly every question can be answered instantaneously. As soon as I considered where to begin my quest, my brain supplied two options. Melnyk's office location in Woolwich or his residential address in Mile End. Given the time of night and the records of the man's habitual behaviour, the better chance was that I'd find him at a licenced eastern European café in Morgan Street where a number of ex-pat Ukrainians seemed to congregate. The idea of going there to eat something and keep a lookout for Melnyk at the same time seemed logical. I wasn't yet familiar with the various shortcuts on the underground, so grabbed a taxi, getting out at the end of the street and walking down towards the café itself. The dark evening was cold and drizzly, so the umbrella did the double service of keeping me dry and less detectable. Despite the crackle of an invoice in one of the pockets, the coat was warm and suitably cloak-and-dagger. Sherlock would have adored this.

The café had a Russian name which, due to poor lighting, a dreadful paint job and my fledgling command of the language read as 'The Old Empire'. What imperial Russians might be doing in east London was anybody's guess, but the place seemed to be reasonably well patronised and the food smelled appetising. I sat at a small table near the back where the lighting was dim. The waiter looked apathetic but perked up when I ordered a large bowl of beef goulash and a bottle of the house red. I had no illusions about the wine, though I had hopes for the goulash.

Waiting for the food gave me the perfect excuse to look around the place. I wasn't expecting to see Melnyk straightaway which was just as well. The thought that he might recognise me from the tailors was a possibility but I was dressed very differently now, was sitting in part-shade and in any case, what reason would Bonneville's nephew have to frequent a shabby café in London's east side? Most people's brains are so lazy.

The meal arrived; a dish of aromatic stew with paprika, potatoes and dumplings. There was also a basket of dark coarse bread. The wine was from Macedonia but the label details were incomprehensible. The waiter simply left the opened bottle and a large glass for me to drink at my own pace. Pouring a small amount, I swirled the ruby liquid before tasting. It was potent but surprisingly mellow. I had drunk worse at Oxford. The goulash was perfect for the weather and despite having had a perfectly acceptable lunch, I was hungry again, often the case when I was absorbing lots of new information.

I ate slowly, pacing myself and making careful note of everyone who came in. Mostly single men and a few couples. Not a place for families, it seemed. There was a small, ill-lit bar on the far corner of the room with tall wooden stools. Several patrons went directly there, making no pretence they'd come for the food. The conversations in the café were mostly eastern European; some Russian, a smattering of Hungarian and what sounded like Czech. In addition to Arabic and Mandarin, I already possessed the Romance languages and recognised various loan words and shared phrasing. I was struck with the notion that learning Slavic idioms might be sensible sooner rather than later. I also felt a sudden need for some sort of weapon and wondered if Bonneville might give me a gun.

I left the wine after a glass as I wanted a clear head but the goulash was delicious and I made a mental note of the café. It would be nice to return in the summer and see how they handled Borscht. Ordering a coffee, I was beginning to wonder if my prey was going to show tonight when the door opened and two men came in together. One was Melnyk, the other man, wearing a long waterproof and a hideous pair of snakeskin cowboy boots, had his face averted. Walking directly to the bar they sat on stools and ordered beer and several shots of vodka, drinking some of the beer before adding a shot of vodka to the larger glass and sipping again. I couldn't vouch for the quality of such a cocktail, but Melnyk and his companion seemed to find it perfectly palatable. I listened carefully, but their voices were too quiet. I was in something of a quandary.

My current seat in the opposite corner was perfect to observe the place generally, without being observed myself. However, my objective was now more specific but too far away; to overhear Melnyk's conversation, I had to be closer. The sign for the lavatories was not far from where the men sat. If I walked past, would he recognise me? I stood as nonchalantly as I could before walking over, my eyes anywhere but on the two men. As I made the doorway of the lavatories, I risked a swift glance, finally observing the face of Melnyk's friend. I had seen that face very recently. In a photograph.

The unknown friend shared a photograph with Melnyk in Bonneville's file. They had both been in uniforms and carrying automatic weapons. My mind's eye could see the caption on the bottom of the photograph and the words became clear. Avel Melnyk and Taras Vovk, Ossetia, 1981. But what was Vovk doing in London? According to notes in Bonneville's folder, Vovk had died during insurgent activities on the outskirts of Abkhazia only months after the photograph had been taken.

I continued into the Gents as I interrogated my memory of Melnyk's file. If that one piece of information was incorrect, it suggested other things might be equally incorrect. What if it hadn't been Melnyk who had betrayed Sir David's colleagues? What if Avel Melnyk was not the villain he'd been painted? Bonneville might be looking for danger in completely the wrong quarter, never identifying the genuine threat until it was too late. I needed another look at Melnyk's file and I wanted to see it tonight before anything else happened. The outer door to the mens' toilets opened and two sets of footsteps entered. I dodged into the nearest cubicle, locked the door and held my breath. It might be anyone, but then I saw the toe of a snakeskin boot underneath the cubicle door and realised I was stuck. In the brighter lighting of the lavatories and in such close quarters, it was probable Melnyk would recognise me. Lowering the lid of the toilet, I sat and waited.

The two men were talking and laughing, partly in English, partly in Ukrainian. There was a mention of a child's birthday and a party; a present was to be purchased. The conversation was light-hearted and not remotely sinister. Melnyk was washing his hands when he mentioned he had met an old friend this afternoon, someone from the war days. It could only have been Bonneville. But there was no rancour in his voice, no anger; no suggestion he was talking about the man who had betrayed him into torture and imprisonment. It was odd. Something was wrong.

Eventually both men left and I listened carefully to the sound of their steps moving away from the toilet doors. I cautiously peered around the outer door just as Melnyk and Vovk left the café through the front entrance. I was more than ever determined to have another look at the file Sir David had shown me that afternoon, and I wanted to see it now, tonight, while unanswered questions flooded my thoughts. This was the other thing about having a near-eidetic memory. I knew I couldn't rest until I had the information I wanted. I had to get into Bonneville's office tonight.

###

It is a lesser-known fact that the centre of British governmental administration never actually closes. After I had returned to the flat to collect my security badge, I grabbed a cab back to Whitehall, retracing my steps until I arrived at the entrance where I'd been given the pass in the first place. There were fewer lights and a lot less people around the place, but Her Majesty's Government was very much open for business. Showing the pass and waiting while my details were scribbled down in a night-register, I strode quickly along the maze of marble halls and passageways until I found myself once more outside the small waiting room. Lights shone through the glass above the door, but would the door itself be locked? Given that the room itself was a place to observe people without them knowing, I hoped the door would open. It did and sudden relief eased my shoulders.

I assumed whoever was on duty would be watching and my assumption was proved correct. The inner door opened and Euan, the same young man who'd escorted me to Bonneville's office that morning, looked at me with very raised eyebrows.

"Mycroft?" he opened the inner door wider to let me through.

"There's a file in Sir David's desk I need to see," I said, ignoring the pleasantries. "I saw something tonight that makes me question some information in the file. If I'm right, Sir David might be in serious danger and utterly unprepared for it."

"You want me to let you into Sir David's office?"

"It's critical you do."

"I can't let you in unaccompanied," Euan sounded troubled.

"I don't care if you want to sit on my bloody knee, just get me in there and let me have that file!"

Whether it was the urgency in my voice or the authority bestowed by knowledge, I had no idea, but Euan nodded and beckoned me down the carpeted passage. Bonneville's office was not locked, a fact that surprised me at first until I thought about it. If everyone in the department knew the secrets, a locked door meant very little. I was positive there would be some confidences Sir David would not want anyone but himself to have, though those would not be kept in his office.

Sitting in Bonneville's chair, I went to the same drawer he'd opened that afternoon. The same heavy file was there and I pulled it out, almost spilling the contents across the wide desk.

"What are you looking for?" Euan stood with his arms folded, a strange expression on his face.

I was scrabbling my way through the thick pile of aging photographs until I found the one I sought; the one with Melnyk and Vovk outside Ossetia. Placing the photo to one side, I dived back into the pile of old documents, hunting the letter I remembered clearly. The one signed by Bonneville, giving Melnyk up to the authorities. It was dated 1985. But if that was correct, then something was wrong somewhere ... I returned to the photograph, lifting it into the light before looking for a magnifying glass which Euan conveniently handed to me. The date on the photo said 1981. Frowning, I switched on Bonneville's desk light, holding the picture directly under its brightness. It was only then I saw the number had been doctored. It wasn't 1981, but 1984. Someone had very carefully removed the slant and cross-stoke of the '4'. Whoever did this knew that Vovk was still alive after 1981 but wanted everyone to believe the man dead and gone.

Why?

I thought back through Sir David's lecture earlier in the day about the difference between genuine information and details that merely seemed genuine. Returning to the list of deals Melnyk had contracted in Eastern Europe after the Russo-Georgian war, the long list of armament transactions stretched back before 1980, the most recent dated 1987. But Melnyk had been in prison from 1985 until 1986 following Bonneville's betrayal. He could not possibly have been responsible for the completion of any contracts during that time. Which meant there had to have been someone else to do the work. Someone whom Melnyk trusted; someone with whom he would share his deepest confidences, with whom he would share the details of his family. A friend. Someone with whom he would go out drinking.

Taras Vovk.

If Taras Vovk's death was falsified in government records, such a thing had been done for one of only two reasons. One, to facilitate the lucrative armaments pipeline between London and Kiev. Two, to wrongly implicate Avel Melnyk in a plot to assassinate Sir David Bonneville. But why? And more importantly, who? I sat back in Bonneville's chair in hard thought.

This cover-up had been in existence since at least 1981. It involved both Vovk as well as someone right here within the British government. Lifting the file and turning it over, I saw a long list of names and signatures on the back; names of the people in whose care this file had rested at one point or another. The very earliest name, the originator of the file, was none other than Sir David Bonneville himself. The date of the file's inception was 1981.

Was Bonneville masterminding a cover up at the highest level? Was Sir David nothing more than a thief bent on feathering his own retirement nest with the healthy profits of eastern European arms deals? I had nothing more than my own assumptions of Sir David's financial circumstances, though given his car, his predilection for thousand-pound suits and lunches in Mayfair, he'd need a damn good income to keep everything together. Perhaps the notion of an untaxable golden parachute had been too tempting to refuse?

But then, why implicate Melnyk? As soon as I asked the question, the answer was obvious. By creating the notion of some shadowy assassin bent on revenge, Bonneville had the perfect excuse to keep his eyes on the arms pipeline and everything that affected it. What was it he had said? He had eyes everywhere. All the better to deceive you with, Little Red Riding Hood. Bonneville had deliberately and cold-bloodedly thrown suspicion on a man he had already condemned to imprisonment and torture, merely to facilitate a series of illegal arms deals. It was entirely likely that the evidence used to condemn Melnyk was equally fabricated.

My stomach knotted. I wasn't sure if I felt sick because of the betrayal I'd just uncovered or the fact that nobody else had. And then, of course, was the question of what I was going to do about it all. I stood abruptly.

"Thank you," I said, piling the file's contents back into the folder, making sure the desk was clear of all the papers. "I have what I wanted, Euan," I nodded. "Thank you for letting me see this. I wouldn't have slept a wink missing this detail," I smiled a little then. "I'm going home now. See you in the morning."

"I'll have to let Sir David know you were in here tonight," Euan was concerned, partly questioning.

"That's fine. I'll be talking to him first thing in any case," I added, rubbing my eyes. "See you in the morning."

Heading back out the way I'd come, I was confident Bonneville already knew I'd been in his office looking at the Melnyk file. If it were my office, I'd have cameras everywhere. I smiled. I'd even have them out in the waiting room. I slowed my stride as I approached the security guards at the building's exit, half expecting a couple of men in dark coats. There were only the same two guards who had let me in thirty minutes before. I swallowed my relief.

It was only as I stepped out into the late evening that I realised Sir David didn't need to have his men here waiting for me at Whitehall; everyone knew where I was living, and someone had keys; the bags from Anderson and Sheppard and the white envelope with the contracts didn't fly in there by themselves. It was obvious I couldn't return to the flat tonight, not without some means of protecting myself.

But this was London, a major capital of the Western world. One of the things this city was not short of was hotels and I had enough cash in my wallet to last for several days. Flagging down a black cab, I told the driver to head south over the river to the cheaper areas. I was looking, I said, for a clean hotel used by business people in the city for only a day or two. Nothing fancy, just clean and anonymous.

The driver said he knew just the place and ended dropping me off in front of Walford's Eurotraveller Hotel. There was a twenty-four-hour reception and even at this time of the evening, there seemed to be a good number of people moving around. Reception was brightly lit and while everything was more reminiscent of a motel, the place was adequate. I booked in for the night. If I hadn't resolved the situation by tomorrow, nowhere was going to be safe. Used to catering for the sometimes disorganised business traveller, the hotel boasted a small shop, also open around the clock. There were business shirts, socks, underwear, sleepwear and toiletries. A rack of cheap paperbacks stood opposite a similar rack of popular medications and chemist-wares. Buying a couple of white shirts and a bag of essential supplies including a spray bottle of deodorant, I took the lift up to my room

Never had I felt more like taking up smoking, but first I wanted to get my thinking in order. Throwing my purchases on the bed and emptying my pockets of all I carried, I found the receipt for the coat and was about to throw it in the bin when several printed details caught my eye.

All the clothes bought at the shop today had gone onto Bonneville's personal account, the details of which were printed out at the bottom of the long piece of paper. Details which included a residential address.

Checking my watch, I saw it was close to eleven. Though it had been a long day, I'd had much longer ones in the last couple of weeks; a few more hours of vigilance wouldn't kill me. Putting the deodorant in my coat pocket and locking my room, I walked out through hotel reception, into the driveway where a cab was just being paid off by a passenger. Hopping into the back seat, I asked to be taken to an address in Albermarle Street, Mayfair. I knew where Sir David Bonneville lived and I was going to find out if he was a traitor.

###

A five-story town-house, elegant, with tall Georgian windows, appropriately situated wrought iron balconies, window boxes and front porch lights. Sir David did not stint himself when it came to the finer things in life. The ground floor had only two lights showing; one in the hallway, illuminating the front door and a second in the room to the left of the door. A sitting room perhaps? I stood across the road in dark shadows, knowing that something was going to happen though not entirely sure what. As my eyes became accustomed to the darkness I realised there was a faint gleam of light at the edge of the door itself. It was partly open.

On a bitter January night with rain and snow in the air, nobody would leave their front door open, not even by accident. Without realising it, I was sprinting across the street and up the few stone steps leading to Bonneville's house. No matter what my suspicions might be, something was terribly wrong here and I needed to know before I chose which side I was going to stand on.

The door swung inwards at my touch and a wave of warmth brushed my face. Closing the door behind me, I headed towards the lit doorway on the left. Moving silently and peering around the frame, I saw Sir David seated in a Chesterfield beside a roaring fire. He was sipping from a brandy balloon and appeared perfectly alright.

"Come in," he said. "I've been expecting you."

Taking a breath, I did as I was bid, stepping further into the light. The sharp surprise on Bonneville's face was almost comical had he not immediately scowled, sitting forward and glaring at me.

"What in damnation are you doing here, Holmes?" he hissed. "I've been setting this little dénouement up for months. What do you mean by barging in here and risking it all?"

I considered. My mentor had no idea of my activities this evening. If he had, his response to my appearance would have been markedly different. Time for explanations later.

"I don't think Avel Melnyk is the man planning to murder you," I spoke quickly. "There are errors in the file; the dates are wrong."

"I know the bloody dates are wrong," Sir David checked his watch, an old Edwardian silver hunter he carried on a waistcoat chain. "I changed them to ensure nobody else would go after Melnyk until I was ready. There is a reason the dates are wrong. Now get the hell away from here!"

There was something in his voice that made me turn and leave without another word. I had no idea what was going on but I seemed to have jumped right in the middle of it. Realising Bonneville was indeed waiting for someone who happened not to be me, I was about to leave the house when I heard soft footsteps on the stone steps beyond the door. Instinctively, I ducked back into the unlit doorway of the room directly opposite the sitting room where Sir David was waiting. I could see and hear everything.

A tall man came in, his back to me. Not bothering to look around, it felt as if he already knew his way around, as if he'd been in the house before. He headed directly for the doorway opposite the one I was hiding inside. It was Melnyk. He stood still, framed in the doorway.

"Avel," though I couldn't see Bonneville in the room, it sounded as though he was still seated. "Come in, old friend."

"I have not been your friend for a very long time, have I, David?" Melnyk's accent did nothing to obscure his words. "I knew today, when we met in the tailors, I could no longer stomach your lying hypocrisy," he snarled. "You betrayed me! You sent me to prison! You gave me to those monsters!"

"Just as you betrayed our friends. You and your brother were happy to murder anyone who got in the way of the shipments; their families and children," Sir David's voice remained composed as Melnyk took a step further into the room.

"Brother? I have no brother."

"Your brother, Taras Vovk," Bonneville replied. "You and he pretended no familial connection so that he would not be captured along with you and could therefore continue the arms deals. The two of you killed everyone who fought for the cause, you were only in it for the money," Sir David paused. "You disgust me."

Melnyk laughed. "You always did know too much, David," he said softly. "Taras and I used to mock your mistaken belief in people," he said. "Though my brother is slightly better with a knife than I am," he paused, reaching into his coat pocket and bringing out a pistol. "Personally, I prefer one of these."

"Killing me won't do you any good," Bonneville sounded weary. "People are already coming for you, though if you murder me, you will never be released this time. Never."

"As if I would give any credence to your poisoned words," Melnyk pointed his gun and fired.

I froze. I simply froze.

I had no weapon other than a bottle of spray deodorant, useless except at close quarters. Melnyk had a gun. I had no experience of unarmed combat and he had killed many times. He was at least five stone heavier than I. If I wanted to help Sir David, I needed not to die. In the two seconds it took this understanding to reach my brain's higher reasoning, Avel Melnyk had already left the house, closing the door behind him with a loud click. I ran into the sitting room, only to see Bonneville slumped back in his chair by the fire, eyes closed and frighteningly still.

"Sir David," I looked for blood, a wound, but nothing was immediately evident. I tried to find a pulse in his wrist, my entire attention focused on locating the bloody thing when all I could feel was the thunder of my own blood roaring around my head.

"Fuck," I forced myself to calm and focus on the soft underside of Bonneville's wrist.

I found a pulse. Moving my fingertips a fraction, I realised it was a strong pulse, a little fast but not indicative of someone who'd just undergone major physical trauma. I slowly raised my eyes, to find myself staring into Sir David's amused gaze.

"Thank you, Mycroft," Bonneville coughed oddly, but waited until I released his arm. "I appreciate your concern but as you can see, I am quite well," he sounded a little breathless.

"Melnyk shot you," I said. "I heard everything."

"Bullet-proof vest," Bonneville patted his chest. "Avel always uses a heart-shot; the chances of him doing anything else were microscopically small. There was a bit of a thump but little more."

I stood, unsure of anything. It was then I saw the small stain of red just above the opening of Sir David's waistcoat.

"You're bleeding."

"Impossible," he scowled again, rapidly undoing buttons until he reached his shirt where a dark stain was spreading rapidly across the white linen.

"Damn," Bonneville sat back in his chair. "The bullet must have been high enough to catch me just above the vest," his voice was suddenly very breathless and he coughed again. "Call an ambulance, there's a good chap," Sir David closed his eyes. "Call the office and tell them where I am, please."

In the next instant, he was unconscious and the blood was not stopping. I grabbed the linen cloth off a side table and pressed it hard against the wound. Reaching into my pocket, I called 999 on my little phone, giving the address and demanding an ambulance, making it clear who the patient would be. I also rang the number of the card Bonneville had given me in Oxford. I wondered if the line would be monitored at this time of night.

"Director's office, may I ask who's calling, please?"

I explained the situation and was told to accompany Sir David in the ambulance. On no account was I to leave him alone before I was relieved by the appropriate personnel at the hospital. Was that entirely clear?

It was.

###

The bullet had nicked Sir David's left lung near the top, but the loss of blood and inability to breathe had triggered a small heart-attack. While measures had been taken to assuage the situation, Bonneville was expected to be unconscious for at least a couple of days while his body recovered from the shock. Though he looked younger, he was seventy-two years old.

I returned to my flat to clean up and sleep for a few hours before heading back in to the office. Not quite yet understanding my position, I nevertheless called for a meeting of senior staff and explained what had happened. I also said that during Sir David's hopefully brief absence, I would fulfil my role as his deputy and, for the time being, would be using his office. Half expecting dissent, I met none at all, not a single curled lip or averted gaze.

Euan was the one who handed me Sir David's still-unsigned order committing one Avel Melnyk to an unspecified term of detention at an unspecified place of confinement.

"How hard do you want our people to go after Melnyk?" Euan sounded hesitant.

"As hard as possible," I nodded, taking the letter.

"Do you know what that actually means?" Euan narrowed his eyes. "To go as hard as possible?"

"I expect it means terminal force," I met his gaze without a blink, understanding in that instant the importance between what was real and what only seemed real, between the things that were written on paper and things that were written on life. Avel Melnyk was a murderer, a traitor, a spy and a thief. He was also stupid and had attempted to put an end to the only man clever enough to have brought him to justice. I did not want Melnyk around to come after Sir David again. Or me.

"Terminal force?" Euan raised his eyebrows.

"Absolutely," I said, signing a man's life away. I fully intended to do this job to the best of my ability for as long as I possibly could and one less enemy made perfect sense.

I sat in Sir David's chair and watched the sky grow dark.