My heart has joined the Thousand, for my friend stopped running today.

They say you never know when your last day on Earth will be. Not even with all our technology and all our science, all our wisdom and art; it remains one of the final mysteries, forever just out of our reach. Perhaps it is a merciful Creator's grace; perhaps it is the last, cruellest twist of Fate. On the Grid, we have all become accustomed to living with the shadow of Death; some of us, like Adam, laugh grimly in its face; others, like Harry, size it up like an old and well-known adversary, never letting it out of their sight; and then there are the rest of us, who simply choose not to look at the darkness, holding it at bay with all the desperation of terrified children, afraid of what lurks beneath the surface. And we succeed, or at least that's what we tell ourselves, until the monster rises up and takes one of us, like a hawk plucking a mouse out of a meadow. Then we remember, and wonder how we could ever have forgotten…

The day begins like any other Thursday in early June, the sun already high over London as I drive towards Thames House. As I work my way through heavy traffic towards Horseferry Road, my phone, perched securely in its hands-free cradle, lights up with an incoming text message: Just wait till you see what I've got ;) It is from Colin, and for a moment I can't think what he means, until I recall a conversation from a week or so ago. Colin must have gotten his hands on the final block of Doctor Who episodes, a month ahead of broadcast. We have watched most of the season as Aunty intended, but Colin being Colin, he has been doggedly trying all his contacts at the BBC, and his perseverance has evidently paid off.

I grin at my reflection in the rear-view mirror, and despite the gruelling hours I have worked this week, I feel childishly pleased at the prospect of gorging on my favourite TV show. The last episode was a good one, the first of a two-parter about an impossible planet and a black hole. I have already set the DVR to record the second part on Saturday, for this week is shaping up as yet another long slog, seemingly with no end in sight. That's how it's been, ever since I returned from Tring: one thing after another piling up, attacks on oil refineries coming hard on the heels of outbreaks of mysterious illnesses, the country seemingly going to rack and ruin under a continuous onslaught of incidents and near-misses, the security services pushed almost to breaking point as we struggle to gain control of the situation, and the media having a field day as it avidly reports on every disaster, every new demonstration, every disgruntled NHS patient waiting in a hospital overrun with hysterical people who believe they have everything from anthrax to the plague. When Adam walked through the pods yesterday, only four weeks after Miss Wells' murderous attack, I had been deeply concerned by his thin, pale appearance, even though everyone else had hailed his return as if the cavalry was finally appearing over the hill. Harry had hustled him straight into the inner sanctum, and shortly after we had all been called to a briefing, Ruth almost trotting towards the meeting room in her eagerness to see them both, each quick, light step of hers like a knife through my heart as I followed her along the corridor with considerably less enthusiasm, maintaining a decent distance between us all the way.

Ruth… she is turning towards Harry more and more every day, like a flower following the sunlight, slowly, almost imperceptibly, and inevitably; for me, it is exquisitely painful to witness. I don't know what's worse, the realisation that I was right all along, or seeing the proof of it playing out before my eyes. I have never been more grateful that our relationship was not general knowledge, nor felt more conflicted. I'm torn between relief that the demise of our relationship is not playing out on the claustrophobic stage of the Grid, and a perverse wish that it were, for then at least the others might understand why I no longer choose to sit next to Ruth in meetings, and keep my distance from her as much as possible, and spend more time than usual in the server room, or the tech suite, or anywhere she isn't. Jo knows, although she says nothing, and Colin. Each have expressed their sympathies in their own ways, Jo by bringing me food at every opportunity, even though I have no appetite, and Colin in his much more direct manner. We have had some long nights in the Cricketers' Arms lately, talking, or not, as the mood takes us, and Colin's verdict each time remains the same. "You're well shot of her, mate. She doesn't deserve you; let her moon after Harry for a bit, instead. It'll do her good." And even though I know he means well, even though I know that he's right, there's no comfort to be had in such robustly sensible advice. There's only loneliness, and a deep, aching longing that refuses to be assuaged with mere good sense and more work than I can manage.

The hardest part is trying to maintain a degree of normality when I am unable to avoid her, for the simplest interaction can turn into a minefield of emotional complexity. Ruth appears oblivious to my inner turmoil; she still smiles at me when we pass in the corridor, chats about work if we both find ourselves in the tea-room at the same time, and listens as intently as ever if I speak to her. Once or twice, she has even touched me; an inadvertent brushing past on her way out of a briefing, or her fingers coming into contact with mine as she gives me a file, with an electric jolt that shakes me out of my carefully constructed semblance of self-composure and leaves me trembling as I fight for control, my nerve endings screaming for just one more second of human warmth…I miss her touch more than anything, that feeling of connection, the acceptance which flowed from her fingers as she stroked and held my middle-aged body, and wrapped herself around my heart…

Or perhaps she's not completely unaware; just yesterday I had found myself alone in the lift with her; I would never have put myself in such a position, except that I had been carrying a stack of files I could hardly see over, and so had not noticed her. As I got in, she had asked in a matter-of-fact tone of voice, "Going up?" as she pushed the button for the Director General's floor. "Ruth. Thank you." I was, in fact, on my way to a briefing with the DG, at Harry's request, to talk through some of the more complex cyber-security challenges we are currently facing, in what feels like a country gone mad. But of course Ruth had known that; there's nothing that happens on the Grid, it seems, that she doesn't know about, for Harry trusts her with everything. A tense silence had filled the space between us, before she had said, "So, how are you, Malcolm?" I had peered uncertainly at her from behind the topmost file, and she had uttered a short, mirthless laugh. "Really, it should be you asking me that, shouldn't it?"

I had shifted the heavy stack of files in my arms, wishing that the DG's office was not on the top floor of Thames House, with sweeping river views from his plush executive suite; the lift ground its way upwards with the speed of a glacier traversing a continent, and all the while Ruth's eyes were fixed on mine, her arms folded tightly across her chest, her body held rigidly. I hadn't known what to say in the face of such overt hostility, and before I could think of an appropriate response, the lift doors slid open and she stalked out first, also headed for the DG's office. I had staggered out beneath my burden and followed her along the soft carpeting and through the oak-panelled hall. At the door of the DG's suite, she had paused, before opening it and gesturing me through with a curt nod of her head. "I…I didn't know you were coming to this briefing too," I had ventured nervously, while she regarded me icily. "Harry's in Whitehall, trying to talk sense to the Home Secretary, so he asked me to sit in for him." There could be no clearer demonstration of Harry's high regard for her, for this is a privilege normally granted only to Adam. "Ruth, I… I'm…" but the words had died on my lips as she shook her head. "Don't. Just, don't. Whatever you're going to say, I don't want to hear it. It's over, done, but we still have to work with each other, so let's keep things professional." And with those words, she had swept through the heavy double doors, and into the DG's presence, leaving me to make my entrance with far less grace as I struggled through with the files. That particular briefing had not gone well...sighing, I pull the Rover into my usual car park beneath Thames House, and close my eyes for a moment, gathering myself for the day ahead.

I'm very glad that Adam is back, for things, as Harry has observed repeatedly over the last week, are rapidly going to Hell in a handbasket. Not a day passes without some new attack or attempt on national security: Al Qaeda is the favoured suspect, for a campaign of disruption on this scale, but I remain unconvinced. There's something strange, something…knowing…about the events of the last month or so. Since Miss Wells died with "DJKARTA IS COMING!" on her lips, the slogan has appeared all over the country, not just in London; the oil refinery attacks were perfectly timed to coincide with an increase in global fuel costs. Just as one might think things couldn't possibly get any worse, the top story on this morning's news was about yet another commuter collapsing on a London bus with blood streaming from every orifice, sparking yet another wave of fear and further taxing the already overburdened health system… it's just too well orchestrated. I could almost suspect that the attacks were being coordinated from within the British establishment itself, but I cannot imagine who would be capable of such breathtaking treason, or why.

There have been threats against the Prime Minister and his family, and Jo has been sent undercover to protect his only child, Rowan, who is up at university. Colin had been more than usually concerned about Jo going into the field alone, and spent several nights developing a device to alert her of intruders in her sleep. When he had demonstrated it, I had been suitably impressed, not only by its elegance, but by the dedication that he had shown. "Colin, this is brilliant!" I had enthused, admiring the neatness of his design, "we must develop a few more like these. I can think of all sorts of applications for this technology. "Yeah, I'm pretty happy with it," he had admitted, "now all I've got to do is make it up to Jill; I had to back out of two dates last week, because of work. She's pretty good about it, especially with things the way they are at the moment, but still. It's not easy to fit it all in, d'you know what I mean?" I had smiled back, pleased that things finally seem to be going his way in the romance department. "It must make it easier, now that she knows what you actually do."

Jill had passed her background vetting with flying colours, and Colin had been quick to let her know what he actually did, much to her surprise; she had thought no more about it when he had described his job as 'IT helpdesk in a government department.' Colin had grinned back, "Yeah, and as for the sex…let's just say it adds an extra something. She calls me her own personal James Bond…" I had blushed to the tips of my ears, unused to such frank discussion of this most intimate of all subjects, and he had shrugged, "Sorry, Malcolm, it's just that it's been such a long time, I feel like shouting it from the rooftops: Colin Wells is finally getting some!" I can't begrudge him his excitement, even though it only serves to highlight the loss of intimacy in my own life: Malcolm Wynn-Jones isn't getting any, and doesn't think he will, ever again. This was such a profoundly depressing thought that I had hastily turned the subject back to Colin's work. "Jo will be thrilled with this, I'm sure." At the mention of Jo, Colin's face had changed, ever so subtly, and I had understood. Somewhere deep within, he still carries a torch for the junior field officer; that's why he had chosen to work back so late. The human heart holds many secrets, some buried so deeply that even its owner cannot know the whole truth…it truly is a rag and bone shop, a veritable midden of old passions and half-dead loves. With this final, cheery observation, I heave myself out of the Rover, and trudge off to the Grid.

I log on, wade through a morass of internal emails and encrypted communications from GCHQ, check Five's firewalls, which have been under increasing attack since all this started, and read Ruth's daily situation report, full of alarming information and with more questions than answers; in particular, I don't like the sound of the sabre-rattling coming from Six, more specifically from one Michael Collingwood, a tall, aristocratic-looking man who is supposedly heading up our sister service's response to the crisis situation which is engulfing Britain. Earlier in the week, following the sudden death of Gerry Houghton, a Cabinet Minister who had apparently committed suicide after being found in possession of child pornography, Harry had raised the possibility that Collingwood might be capable of launching an attack himself, in a bid to force the government to declare martial law; but I cannot believe that any member of Her Majesty's security services could even contemplate such a thing, and certainly not one with the distinguished career that Collingwood has enjoyed.

At one point, Harry had actually gone so far as to suggest that Houghton might have been dispatched by Collingwood, but this is a speculation I want no part of: Surely he can't be serious? had been my initial thought, until I had realised that he was, very much so. Harry's played the spy game for longer than any of us, and so I'm willing to give him the benefit of the doubt, but until I see some concrete evidence to back up his theory, I am reluctant to subscribe to it in its entirety. The presumption of innocence until proven guilty…it's the cornerstone of our whole society, really, and I refuse to let go of it, for it is part of what makes me so proud to be British, even with the nation in the state it's currently in. I work solidly for an hour or so, and then I go in search of Colin; he must be in, if the MP3 player charging on his desk is any indication. Usually, he's inseparable from it, but I haven't seen him today.

I can't find him anywhere, or at least he doesn't seem to be anywhere on this side of the pods. I look for him in all the usual spots; the server room, the tech suite, the staff canteen, and even up on the roof, where we all disappear sometimes when in need of five minutes' peace and a bit of fresh air. Finally, I ask Ruth in passing, much as I hate having to admit that I don't know where my offsider and best friend is. She barely stops to look at me as she hastens towards Harry's office yet again, her nose in a dossier. "Ah, he's got a pass for the day," she tells me dismissively over her shoulder, "he's on surveillance watching one of Collingwood's men," and then she is gone. I frown, for Colin is my staff member, and strictly speaking, this should have been cleared with me first; next, I spot Adam looking apologetic on the other side of the floor, and understand that he must have co-opted Colin.

I raise my shoulders in a 'what's going on?' gesture, and Adam comes towards me, not moving with his usual easy stride, but with a slight hitch in his left leg, a reminder that he is only four weeks out of major surgery. "Sorry, Malcolm, I know I should have checked with you first, but we really need eyes and ears on this bloke from Six and we're overstretched, what with Jo out in the field and me only just back and so much going on at once. Colin offered to help, if that makes any difference, and he said that he didn't think you'd mind." I look at him sharply, but his deep blue eyes are clear and guileless: he is telling the truth. "Well, I suppose that's OK, given the circumstances, but in future I would appreciate at least being told before my junior is deployed in the field. I'm responsible for him, you know." Adam nods, and we part ways, he to Harry's office, and me to my desk, situated in what is now uncomfortably close proximity to Ruth, to check in with Colin.

"Zebra Three," I open with his designated call-sign, and am pleased to hear him respond, more or less correctly, with, "Hello Big Bird, it's tricky, this five across." He means the Daily Telegraph cryptic crossword, of course, but I haven't had a chance this past week to so much as look at a crossword, much less solve it. There is some electrostatic interference in the form of a beeping noise, and then I hear him say, "That's strange…it's giving them access to flight numbers and airlines, it's pretty sophisticated kit…oh, my God, they're mapping the heavens!" I can't think what he is referring to, until Colin adds urgently, "Malcolm, I've hacked into their computer (of course you have, I add mentally) and you're not going to believe this. They're focusing on two flights in particular, taking them off their normal flight path. It's a dress rehearsal for crashing two passenger planes into each other over London." Then the electrostatic interference returns in the form of persistent crackling, and I try his call-sign again, while my brain processes the shocking intel he has just reported. "Zebra Three?" Nothing…feeling slightly anxious now, I say "Zeb…Colin, can you hear me?" I'm acutely aware that Ruth has turned towards me, listening. "What's wrong?" she wants to know and striving for nonchalance, I say as off-handedly as I can, "Nothing. Just lost Colin, comms are down." When he brings the van back, we really will have to think about how we might boost the signal to prevent such annoying occurrences: is it too much to ask, in this day and age, for reliable comms when in the field? I think not…

At a loose end, and still feeling unaccountably nervous in the wake of the comms drop-out, I wander over to his desk and spot his chunky little MP3 player, still happily charging away. I think back to his earlier text message, and with a flash of intuition, it occurs to me that he could have stored the Doctor Who episode files on this device; I seem to recall he tinkered with it recently to exponentially increase its memory capacity. Curious, I pick it up and push the central button, hoping to unlock it. The device immediately responds to my touch by displaying a message onscreen, backed by the image of a glaring Colin: HANDS OFF MALCOLM YOU ARE BEING WATCHED, it warns me in bold yellow letters.

Chuckling, I examine the interface more closely, and yes, there it is: a tiny fingerprint sensor, overlaid on the main button. Colin has been getting more and more interested in this sort of thing, modifying everyday technology to suit our purposes, and between this and what he has made for Jo, he is becoming very good indeed at it. I suspect that the message has only recently been uploaded; in the image, he has on the same shirt as he had worn only yesterday, and this only serves to heighten my suspicion that the player does, indeed, hold the final episodes of the season. Well, we shall no doubt get an opportunity to sit down and watch them together, once this current crisis is over. Ruth glances over at me, her expression somewhere between annoyance and impatience. "Don't you have anything better to do?" she asks brusquely, and hurt by her inference that I'm wasting time, I take myself off to the cool, clean sanctuary of the server room, where I spend an hour going over the raw data feeds from Colin's van, trying to pinpoint the cause of the comms failure.

Before I can make sense of it all – there are some upstream frequency-cycling anomalies that to my mind look oddly like the comms were being tapped, but as if Five were somehow listening in to itself – I become aware that I am no longer alone. The hairs on the back of my neck begin to rise as I turn around to find Ruth watching me. "I'd like to go over the latest intel with you before taking it back to Harry and Adam," she says in a normal enough tone of voice, then, tipping her head towards my improvised workstation, she asks warmly, "Any luck working out what happened?" I look back at my screens, and for a moment it's as if we were never apart. "Yes, and no," I begin, and she interrupts, "Sorry, but I'm freezing in here, let's go to the meeting room instead, shall we?" Getting up, I unthinkingly take off my suit jacket as if to drape it over her shoulders, but she shakes her head. "I'll be fine once we're out of this icebox," she says, pulling her own clothing closer and wrapping her arms around her for warmth as she leads the way; and after a second of confusion, I sadly put my jacket back on, and follow her at a safe distance towards the briefing room.

What? NO. I don't believe it. Harry must be playing some sort of sick, twisted trick…I gawp up at him from my place at the conference table as he repeats what he has just said, but there is a sudden, loud, buzzing in my ears and my heart seems to be forcing its way out of my chest via my throat…with a great effort, I manage to gasp, "It's not true!" and my voice sounds strange in my ears, as if it is being produced from a synthesiser, warped beyond recognition. I am vaguely aware of Ruth's hand on my arm, then of her feeling through my pockets, presumably looking for my inhaler, but I push her away and try to stand up on legs that have turned to water, my eyes locked on Harry's.

"Say it's not true!" I demand shakily, but those fierce amber eyes look back into mine implacably as he repeats the unbelievable, unthinkable, unacceptably obscene words: "I'm sorry, but Colin is dead; his body's been found hanging in the woods near Runnymede. He appears to have been killed, as he was found with his hands tied behind his back, and the noose was expertly tied." No, no, no, no, no, no…not Colin, not my best friend, my almost-brother, my equal in geekery and all things technological. Not Colin, who has just found love with a chemistry teacher from Crouch End. Not Colin, with his kind brown eyes and his common sense and a whole family of people who love him…his parents and his brothers, his nephews and nieces, the mates that he goes to the football with…and all of us here. Not Colin, please God not Colin… But God, if He even exists, which I have just begun to seriously doubt, is not listening. Why did I ever think that He was good, or kind? He is nothing more than an impersonal Deity, looking down upon tiny humans as we in turn would look down upon a swarm of ants… remote, distant, and completely unmoved by the chaos left in the wake of His passing.

I feel my gorge rising, and before I humiliate myself completely, I make my way unsteadily from the room, but get no further than the door before the racking sobs that are rising from deep within take on an even more tangible form, and I begin to dry-heave, clinging desperately to the doorframe as I retch and vomit until there is nothing left. "Shock," Harry says drily, stepping around my mess and into the corridor, "Get a medico up here, Ruth, would you, and someone from Building Services to take care of that?" I crumple to the floor, put my head between my knees, and concentrate very hard on the few square inches of carpet in front of me, fighting back the secondary nausea that rises after the body has violently rejected everything in it. Ruth's feet stop in front of me, and I feel her intolerably soft touch on my hand.

"Malcolm, I'm so sorry about Colin," she begins, but I shrink away from her, into myself, withdrawing completely. Her feet go away then, and I am left to stare at the ugly grey industrial carpet until I hear two things: the sound of a mop and bucket being deployed in the corridor, and the voice of Dr Sally Chapman, addressing me from somewhere very near. "Malcolm? Malcolm, let me have a look at you, please," she says, resting her hand lightly on my shoulder, and slowly, reluctantly, I lift my head until I meet those startlingly violet eyes, framed in a face that radiates professional concern. "You're as white as a ghost, but your pupils are enormous," she informs me as her long, cool fingers wrap around my wrist, "your skin is clammy, your pulse is thready, and you're trembling. Severe shock, is my diagnosis, not an asthmatic episode. So, what's happened?" I stare at her uncomprehendingly, and she draws a sharp breath as she crouches down to look me in the eye. "Wait; didn't I just hear that there's been a death in the field?" and I realise that Ruth has told her nothing. I gaze back at her silently, and when I can bear her kind scrutiny no longer, I say in a voice that doesn't belong to me, "Colin's been killed," and I recognise the dreadful ring of truth in those three little words, and the pain in my chest first squeezes in tight, then bursts outwards in all directions like a star gone nova, scattering throughout the universe in a searing blaze of destruction as, to my complete horror and embarrassment, I begin to cry in front of this very nice, very attractive lady doctor. I think I hear her mutter, "This bloody job," and then, "To hell with professional boundaries," as she sits down next to me, offering the reassurance and comfort of her physical presence. "Tell me about it, when you're ready, if you like," she says, handing me a handkerchief, and this simple gesture of kindness undoes me completely. I weep for Colin, for his family, for Jill, whom he had just begun to love, but most of all I weep for myself; what will become of me, now that my best friend is gone?

I dread to think.

A/N: The quote at the start of this chapter is from Watership Down, by Richard Adams. In the UK, 'Aunty' is an affectionate nickname for the British Broadcasting Corporation, or BBC.