I had always been so good at compartmentalising. Work was work: time-consuming, but not worth sweating the small stuff. I never lost sleep in the early hours of the morning over impossible deadlines, or trust beneficiary disputes, not even a regulator visit. I'd say to myself: Christopher, you're better than that; not like the others, bricking it every time the regulator asks you a tricky question. What are your systems and processes to maintain the currency of your Business Risk Assessment? What is your percentage of outstanding compliance review points at the end of each quarter? Didn't even raise a sweat. Cleverest man in offshore, me. But then Mr. V came along. Mr blasted, bloody V. The Singapore job is going away now, I know that. If I could just get to Maurice at Sino Trust and explain to him – I would never have got involved if I'd known. If I'd known. Of course, it was my job to know, yes I understand that, but really – how could I be blamed?

     I'm not alone out here. There are other walkers at night; I've even begun to recognize a few of them. Some of them are shift workers on their way home, some drunks. The occasional bike whizzes past on the cycle path – who on earth rides a bike at two in the morning? I'm fairly sure some of these walkers are cruising: I've been followed a couple of times by men who keep pace with me for ten minutes or so; thanks but no thanks, matey. They give up when I doggedly trudge a straight line with my head down. I keep to the seafront under the lights.

     White lights string along the entire stretch of front between town and Saint Aubin, lighting my way in a three-mile curve. They mark the line between land and sea, the dark all the deeper for their spots of brightness. When I was a kid, the bulbs were a cheerful red, yellow and blue, tackily lighting up the tourists in hotels and guesthouses on the main road. It's a long time since they've gone. The tourists are mostly gone, too, anyway. It's less stick of rock and sandcastles around here, more Ferraris and financial management. I check the time on my Breitling Navitimer, squinting at the dial in the dim light. Wish I'd kept my phone now; without my reading glasses, it's all a blur. If I can just keep walking, I can burn off some of this nervous energy. I need to walk until I'm exhausted, until I can convince myself that this rapid, stuttering heartbeat of mine is the result of exercise. I just want some sleep, for god's sake. Mr. V haunts my dreams, waking me in the night with his request for a "small favour."

Zurich. That damned conference. I thought I was being clever, going back to an industry conference in old Europe when the rest of the directors at work were heading to Asia, Africa, or the Middle East. I was sure there were still relationships to be exploited in Switzerland; plenty of one-man-band fiduciaries couldn't handle the new Swiss rules on trust management. They needed a safe pair of hands to steer them into harbour, and that could be me, Captain Christopher, at your service. Besides, I had plenty of existing relationships in Zurich that could do with some attention. I was going to make the conference, glad-hand some clients, visit a select few bankers and tax advisors and be home in four days without breaking a sweat.

     The conference itself was the usual mix of fake bonhomie and casual cynicism. A whiff of desperation rising up over the mingles and pre-panel drinks: who has the money, who has the access? I passed out business cards to new faces, slapped the backs of old friends, and promised to catch up for drinks with at least five more contacts than I had time for. Business as usual. By the last afternoon of the conference, I was done. I was just contemplating skipping the last panel debate (trustee duties to vulnerable beneficiaries) when a small, dapper man in a dark Brioni suit approached.

     "Excuse me. Forgive the interruption, but are you Christopher Vénal?"

     "Yes, for my sins. What can I do for you?"

     "It is not I who needs your assistance; however, I have a client whom I think would be very interested in meeting with you. He needs some advice, possibly a new structure." He tipped his head to one side, looking up at me with shrewd eyes.

     "He is unhappy with his current trustees – you know the old story. They get comfortable with a client; they forget to provide the correct service, they treat him badly – you understand?"

     "Indeed I do, and I always think it's terribly short-sighted. A happy client makes for a long-lasting relationship – and we all like those, don't we?"

     "Naturally, I have heard of your reputation, Mr. Vénal, and I believe you and my client would deal extremely well together. There is a pleasing coincidence in your names, also. He too is a 'Mr. V'."

     I laughed, though I don't know why particularly; I'd never been called Mr. V in my life. We agreed to meet at the office of Herr Gruber the following afternoon, just before my flight back to Jersey.

     Herr Gruber's client was an ultra-high net worth individual: very old money freshened with a new investment twist. I liked Gruber's estimate of this Mr. V's total worth – in the hundreds of millions of Euros, possibly a billion, all in. I agreed that my trust company could very likely help Mr. V, subject to the usual due diligence process, which I was sure would be a very straightforward matter. It wouldn't be, of course, but you always had to say that – smooth the way ahead. We could establish a new trust to hold all of Mr. V's many assets and investment opportunities: the numbered bank accounts, the private companies holding luxury cars, houses, and apartments around the world, the limited partnership running a fund in Luxembourg. I promised that the trustees would work closely with Mr. V to ensure his wealth was securely and discreetly preserved for future generations, for an appropriate fee, of course. Herr Gruber promised to arrange an introduction to Mr. V as soon as he was back from finalising a casino purchase in Macau, another long-term investment for his many millions.

     Herr Gruber sent me all the documents the compliance team asked for: a neatly completed application form, signed in a subtle mauve ink, a notarized passport copy (Swiss passport, not Mr. V's original nationality), and two proofs of address showing a residence on Lac Léman just outside of Lausanne. It was an uncannily perfect application, and for once, I saw plain sailing ahead. Then bloody compliance came back asking why there was no social media profile on Mr. V and so little reporting? There had been no criminal prosecutions or investigations against him, but why was such a rich and powerful man so hard to find on Google? I mean, compliance complaining that it couldn't find any bad news about a client? Don't they know when to count their blessings? We could bill at least two hundred grand a year on this trust, probably more to come if we looked after him right. A man that rich can buy as much privacy as he likes. I agreed to call Herr Gruber and deal with all the issues. And I had, in a way. An hour after leaving a message for Herr Gruber, Kenneth in compliance came back with print-outs of several innocuous media references to Mr. V.

     "They appeared. Just like that, when I ran the search again."

     "Did you spell his name wrong the first time?"

     "Funny Chris, you should have been a comedian." Ken leaned his lugubrious face over my desktop monitor and lowered his voice. "Something smells off."

     "You're just jealous."

     "Don't give up the day job, Chris. See you at the new business committee meeting."

     This is what it means to be powerful – to reveal and conceal at the click of a mouse. I'd smiled at the prospect: I wanted some of that.

I met Mr. V just once, which seems strange when I feel I know him so well. But my memories of that day are slightly foggy, as misty as the Geneva weather when I arrived. Whisked up to Mr. V's house by the lake in a private car, I met my new client standing on the stone terrace looking out across the water.

     "My apologies, Mr. Vénal – may I call you Christopher? Our weather has not made you welcome. Usually, we would be looking out across the lake to the mountains, but today we just get damp hair."

     He was unassuming in appearance, matching me in height and build, his voice mild and oddly flavourless. Somehow the misty day made it hard to focus on Mr. V's face. Droplets glittered on our heads and shoulders, gleaming in the occasional spur of light shining through the gloom. My hands were wet, and runnels of water dripped down my fingers and onto my Bottega Veneta briefcase. We spoke at length but, when I looked at my meeting notes, I didn't recall any of the conversations I had recorded. I took off from Geneva airport under the general impression that Mr. V was an ideal client, one who perfectly understood the hoops a modern trustee had to go through to accept his business. The details are lost in the fog. One thing I was sure of: I didn't want to disappoint my new client. And yet, here we are. I can feel the wind getting up as I walk the sea wall. The tide is coming in, and I smell rotting seaweed on the wet sand.

Back in the office, the trustee machine churned on. I was already holding funds for Mr. V in a client account, ready to settle into the trust and begin to invest. Astonishingly, as soon as the trust deed was signed, again in mauve ink, everything went without a hitch. Bank accounts opened without delay; shares were issued to the trustee, almost before they were asked for; lists of artworks held in vaults, or loaned to museums, arrived in my in-tray with assurances from the holders that they would only act under my instruction from now on. One morning I received a parcel of gold cloisonné fountain pens, Chinese antiques, for putting into a bank safe deposit. They arrived in the same courier as the bespoke shoes I had on order from Italy. In the same box. I wondered how, briefly, before filling one of the pens with ink. It would be fitting to sign the trustee minutes with this. I looked down at the strands of ownership and control across the structure and found myself at the top, an apex predator in handmade shoes.

     After that, all my time was taken up with Mr. V. I expected it: he was a huge client, the biggest our small company had ever taken on. He would call me first thing in the morning, setting out his requirements for the day's transactions; he would call me at night while I was eating dinner or sitting on the sofa watching Britain's Got Talent with Fiona. He'd speak for an hour at a time, but afterward, I could never quite remember the details. Fiona waited for me on the couch for a while, cup of tea getting colder as I listened and listened to Mr. V's quiet instructions. She must have left at some point; I didn't notice her go until I got into bed that night and found a cold space where my wife should be. Fiona started making plans with friends most nights after that. That worked better for me. I could concentrate when I was alone, listening to Mr. V's soft, almost accentless voice, knowing that I would do anything to keep him happy. The blue light of the phone shone each night in our darkened bedroom.

     As the weeks passed, I felt as though Mr. V and I were getting closer, so close as to almost be the same: we had the same goals, the same drive, the same attitude. Or so I thought. I've always been driven. In my final year at university, my tutor suggested a Ph.D.; he'd be willing to supervise me if I stayed on. I wasn't interested.

     "What do you want, Christopher?" he asked me.

     "I want everything. I want to win."

     Late for dinner, I left Dr. Rix and raced towards the hall. "Mr. Vénal!" The porter shouted indignantly as I walked unauthorised across the sodden quad grass, "Mr. Vénal!" and I sauntered into formal hall to read grace with the pale streak of a worm squashed beneath the sole of my shoe.

I built the business around Mr. V's structure, like an oyster encompassing a pearl. We had the resources now: I had a dedicated team just for this work; we were an office inside an office, largely autonomous from the rest of the business. I fed on the life of the transactions, each one a glittering, dancing joy to control and complete. Here came the portfolios, the currency accounts, there went the art, the whole galleries. Structure after structure built into a dazzling web of ownership with me holding the strings, pulling on the strands to make each part dance. I sucked the life out of them; each completed task gave me a greater sense of power. Pull a thread in Jersey, a toe in Bermuda twitches, a pulse beats in Luxembourg; pull a thread in Nevis and an eyelid flickers, a tongue jerks – the whole thing was coming to life. I was dancing, I was the best, I was the cleverest man in offshore, and I had the control to prove it. This was the life I chose. I was the centre of the web, the world. I win.

Just a small favour, he said — just a small thing, in the grand scheme of what we had already achieved together. Mr. V had a tip for a high-risk investment, but worth it for the returns, he said. He'd been working on this deal for the last two years; it was nearly ready. Mining. Diamond mining in the East African Congo: activity risk piled on country risk piled on sanctions and war. What a combination. The trustees were going to find this one a hard ask, I knew. Mr. V relied on me to make it right; he knew he could rely on me, his right-hand man – his right hand. I looked at the proposal – the returns looked spectacular, the deadline to invest: two days. This was impossible: we needed a full board meeting of the trustee for this, compliance needed to sign off on the proposal. We had no documents on the investment, just Mr. V's word. God, that conversation with Ken was humiliating.

     "Sorry, Chris, you said what? Diamond mining in the Congo? Are you having a laugh?"

     "Come on, Ken, look at the proposal. There are millions to be made from a measly five hundred thousand investment."

     "Is this Mr. V of yours a Nigerian prince?"

     "Ha, ha. Come on. You said yourself, compliance doesn't approve business. That's down to the directors."

     "Yes, and the directors would be insane to go with this. It's a classic: high risk, ridiculous time frame. You know we're in Suspicious Activity Report territory here, right?"

     "Look, I'll talk to the other directors; I can make them see sense."

     "Just so you know, my official recommendation is that we don't touch this with a ten-foot barge pole wearing hazmat suits."

     "Get lost, Ken."

     "If this goes ahead, I'll be expecting SARs from you and all your team, understand?"

     "I'm not suspicious!"

     "You should be."

     Ken had been right, of course, the bastard. Nobody would consider it, not even Dudley, who was usually the most malleable member of the board, our walking example of nice but dim.

     "Sorry, Chris, just not my cup of tea, you know. This high-risk stuff. Leave it all to you, don't we?"

     "Exactly! This is my area; leave it to me. You can trust me to sort it all out." Dudley looked at me oddly.

     "Can we, Chris?"

     He moved away, mobile phone in hand. Probably off to make another 'coffee' meeting down the pub with his mates at the Commission. Really, what was the point of him? Useless fucker in a horrible suit, I was worth ten of him. I knew I'd need to do something more to get this transaction off the ground.

I hear the sea getting closer, whispering in my ear. Or is it the sea? Despite these walks, I haunt myself. Different Christophers loom out of the dark at me, springing up out of the sea into my path. I remember the last day of my first term at university. I'd spent most of it friendless, the proverbial fish out of water. Everyone else seemed to arrive with plenty of school friends; I'd been the first Oxbridge student my school had ever had. Wandering round in a daze, I'd look at my cohort and think: these are the weirdest bunch of people I've ever met. That night it was dark by four o'clock, and the indigo sky was clear. Before dinner in hall, I bought a bottle of the cheapest red I could find on the bottom shelf of Oddbins, then wandered out and across into Trinity. The college lamps were lit, and the warm sand of the stones framed brightly lit rooms, the dark rectangle of grass was perfectly mowed. I could hear an organ scholar practising for the Michaelmas service inside the chapel. As I headed onto the backs, the evening star appeared overhead, and I was suddenly filled with a sense of righteousness, even exultation. This was my place, these were my people. Greatness was coming: I was both the teller and the tale. I have never come close to that feeling again. I disappointed Dr. Rix; I know that. Back then, I didn't care. Now I'm disappointing everyone: my wife, my MD, colleagues. The regulator, oh Christ, the regulator. My thoughts veer away from the memory of that call from the Financial Services Commission. Focus on the walk, keep your heart rate up. Keep walking, and eventually, the sun will come up.

The favour. I was blocked everywhere, and time was running out. I couldn't let this happen; I wasn't going to let this perfect opportunity pass us by. I was in control of this structure, it was my creation, and I was going to make damned sure we didn't fail Mr. V. I considered the options. Nothing official was going to happen, and I wasn't going to get away with making a distribution up to Mr. V to make the investment himself. That wasn't his style. The whole point of this structure was so he didn't have to do anything; it's not his signature on the agreements; he didn't transfer the funds. I did that for him, and it was my call. And then it came to me. It felt like the most obvious thing in the world: do this, and everything will be alright; Mr. V will get what he wants, the trust will have a guaranteed investment return. I would pull the strings and jerk the legs of this structure all the way to the bank. I could send the cash. I had bank access, and I just needed a second authorisation to release the funds. It wasn't even a huge amount; I could use a B signatory as the second authorisation, no need to involve any of the other directors. The decision was so simple that it was almost as though it wasn't really a decision at all – I just saw the way the world needed to be. I would prepare the online bank instruction, make the first approval, and then use the bank token and password from the Senior Manager on my team for the second. She's a nice enough girl, Michelle, competent to a certain level but simply not that bright. School leaver into the job, one of the rank and file. She kept her bank tokens in her desk drawer inside a Power Rangers lunchbox, a relic of one of her kids, I think. It was easy enough to come back to the office that evening and find the right one. She didn't even lock her desk – it was like she was offering it up to me. Michelle had helpfully left her passwords inside the lunchbox in a little notebook. Tut, tut, Michelle, I'll have to have a word with you about that at your next appraisal. But thank you: it makes my life much easier.

     After I sent the cash across, I signed the investment memorandum with my gold pen and scanned a copy across to Mr. V, with confirmation that funds were on the way. He called to thank me, and that was the last time we ever spoke. My triumph didn't last long; looking back, I'm amazed I didn't see how this would go. It was the bookkeepers that did for me in the end, hived off in some dark corner of the office, going through the bank statements. Julie couldn't reconcile the five hundred grand against any trustee minutes or agreements – could Michelle help? I felt the change in the office that morning as I came in late; I could feel the twang in the webs surrounding me – something was up. And then there was Ken, with our MD, and there was Dudley half-hiding behind him, the little coward, and there was Michelle sitting in his office with tissues crumpled in her hands, looking pale and betrayed. This was it — the end.

     From home, on 'gardening leave, I made frantic calls to Mr. V, trying to get him to confirm that the transaction was authorised, that he would indemnify us against everything I had done on his behalf, at his request. But my calls went unanswered; even Herr Gruber was unavailable each time I rang. Mr. V abandoned me after everything I did for him after we had achieved so much together, by his design. I was alone with this. Suddenly there I was, stuck in the spotlight. Those assets were in my control; those transactions were made by me. Those crimes were mine. That signature on the investment document might as well have been signed in my own blood. The inevitability of it hit me: to all intents and purposes, I was Mr. V; perhaps that's why my face in the mirror looked so strange.

The wind is whipping up, and the tide has reached the sea wall; I approach the Catholic church at Saint Aubin, its front looming high and dark next to the white-painted houses alongside. Looking back along the route, I see waves splashing up over the wall and onto the pavement. I've gone almost as far as it's possible to go, but my heart still races, my shoulders are still hunched tight to my ears. The marina. I can walk around the marina before turning back. I walk on. I see Fiona's face wet with tears; I walk on. I see Herr Gruber's dapper shoes tapping on the floor as he waits for me; I keep walking. I see all the papers I signed, the deeds, the payments; I walk on. The letter from the Commission appears in front of me, the notice of investigation, the search warrant; I start to run.

     The marina at St Aubin – the clattering of rigging against mast, the rattling of bones. I lean over the railings, looking down at my unfamiliar face reflected in the water. Mr. V rises from the shadows of the sea.

     "Ah, Christopher, you're here at last."