The snitch tells him to run, so he runs.
       There's no reason, just. . .an imperative.
       One moment he's like any other gray-faced, anonymous wage slave snatching a sandwich and a breath of stale city air, then--
       Something...
       He's running through the side streets as if his life depends on it. (Does it? He's not sure. Maybe.) He splashes through sidewalk puddles left by a late morning shower. The breeze on his face feels good, the sudden pounding of the pulse in his head, the hard slap of impractical shoes against paving slabs--it all feels so good! (And wrong. Very wrong.)
       [Left] , the snitch says and he turns left, veering across the road into a narrow backstreet, almost struck by a slow-moving cab which judders to a halt as baked-in safety algorithms apply emergency braking. Its passenger shouts something through the window, but the words are lost in the buzz that fills his head, and he's already long gone. (This all feels too real for a dream. I'm too alive. Yet somehow, this isn't me).
       He bursts onto a bustling thoroughfare, the snitch staying silent and letting him choose which way. Uh-- Westwards feels promising.
       [Anger. Are you feeling it?]
       He is. The sidewalks throng with tourists and window shoppers, parents with buggies, office drones dressed in smart-cas poking at their phones, a few drunks and crazies too. He barges through them all, momentum carrying the day as he shoves bodies aside like so much flotsam on a falling tide.
       People shout. Curse. He leaves a growing wake of chaos behind. More distanced bystanders stare or point, but he barely notices. His feet and hands do their own thing, clear a path. His eyes stay fixed on some distant point not yet in focus, his brain slaved to the snitch, awaiting its next instruction.
       "Hey!" A man steps into his path. He's tall and heavily built, arms raised as if to bar the way.
       The snitch speaks a single word inside his head.
       [No.]
       His opponent has bulk in his favor, but momentum is the trump card in this encounter. Plus, he's running hard now, moving fast. His elbow comes up and out. The tip connects with the fleshy part of the man's nose. Droplets of blood fly in an arc as the man is flung aside, with a bellow of pain.
       He runs on without breaking step.
       He'd stop if he could. This is wrong. This isn't him. But. . .the urge. . .is loose now inside his brain, and he doesn't know how to put it back in its cage. It's like the instant before a sneeze: a powerful, animal-like urge, impossible to resist. Like an itch that must be scratched.
       [Turn right.]
       He swerves across the road. The traffic is slow-moving, but twin lines of vehicles twitch and halt as controlling algorithms sense the danger and compute the appropriate braking maneuvers. He turns down a quiet side street with its faintly dilapidated townhouses towards a leafy square beyond.
       Some part of him enjoys this, and the realization sickens him. It revels in not having to think, not having to decide how to act. Living in the moment. Such liberation is intoxicating! But who is this person he's become? He can't quite remember, but that's okay because the snitch is doing the thinking for him, removing choices.
       Except-- Some small, still-sane part of his mind cowers in the darkness. Powerless. Watching--because watching is all it can do. Silently, it weeps.
       There's a row of identical citi-sprint cars parked at the curb, umbilicals trailing to their charging pillars. Something about their almost cartoon-like roundness--an urban caricature of a child's bubble-car drawing--incenses him. When he sees how easily one of the little vehicles rocks on its chassis with minimal effort, the snitch speaks.
       [Do it.]
       Momentum builds each time he shoves, and soon the car rocks violently from side to side. He goes with the rhythm, grunts with the exertion. Lifts. The car flips right over, plastic side panels grinding against tarmac. The rounded sides tip it the rest of the way onto its roof. There's a pop! Crazy-paving cracks spread across the windshield while the car does a slow pirouette on its roof, like an up-ended maybug.
       Somebody down the street shouts at him, but he ignores them. Another two cars are flipped before a crowd begins to gather.
       [Time to go.]
       He spares a backward glance. It's as though some outsize toddler has scattered toy cars across the nursery floor. One of them still twirls prettily on its roof, looping its umbilical round itself.
       He can't help but laugh.
       (Inside, he cries.)
       Running again. Running for the sheer joy of movement and the breeze against his face and the way the world blurs just a little as he speeds on.
       The square looms ahead, a railing-enclosed oasis of grass at its center. A pain grows in his chest, and there's a prickling behind his eyes. Terraces of tall, frowning townhouses surrounding the park grow a little blurry in his vision.
       [Breathe.]
       So, he slows to a jogging pace. Today the park is popular; people fill the benches, and scattered groups stretch out on the grass. Mature plane trees throw a chequerboard of light and shade everywhere. A couple lounges on a picnic blanket nearby. They haven't seen him yet. Their faces are inches apart, and rapt expressions suggest no time for anything beyond their own private universe. They look as if they are about to share a kiss.
       An image he's been staring at most of the night fills his head. Backlit hero and heroine gazing at each other, love and desperation in their eyes, while behind them flames engulf a building. He forgets the storyline that has brought them here. He forgets what the building is or why it matters. He forgets because all that really matters are the flames. The flames are his. His job. His responsibility to create. People think the algorithms for fire are easy to code, a post-prod effect to be called up at the click of a mouse--but they're really not. Not these flames. These flames have to be special. They are supposed to rise up out of the inferno, little creeping fingers of light reaching out towards the oblivious hero and heroine. Deliberately, they must beckon and enfold in one final, fiery embrace.
       Painstakingly, he carved pixels into ghost-shadow eyes that peer from the flickering red heart of the fire--eyes, and maybe just the hint of a face. He's been working on this sequence for weeks now, and still, it's not right. He's stared at those flames until they are seared onto his retinas, tweaking and smoothing, but it's still not the picture he sees in his mind. Not how he needs it to be.
       Now, with a critical eye, he appraises the couple sitting in their patch of dappled sunlight. Do they look real enough? Believable?
       Not really. Not in his professional judgement.
       [Then erase. Wipe the data. Start afresh.]
       His feet slow him to a walk. He moves like a sleepwalker towards the couple on the grass.
       Erase? He's not sure he knows how to do that.
       But he can destroy.
       (Think! The sane part of his mind is pleading. It pounds on the imprisoning walls, fighting against the darkness to be heard. It's such a tiny voice though; distant and indistinct. This is wrong, it screams. Don't you remember the bad times before? Don't you remember why they put the limiter inside your head?)
       He doesn't have to listen to that voice. The snitch is in charge. It makes the decisions.
       The couple looks up as his shadow falls over them. Irritation on the man's face. Something else (guilt?) on hers. He takes another step towards them, snarling like some wild animal, sending flecks of spittle glinting in the sunlight. Bottles and food cartons scatter as he kicks out. His heel stamps down on the phone that has slipped from the woman's hand. He pivots, aiming a vicious kick at head-height, but they scrabble back just in time, out of range.
       The woman is screaming. People shout and run: some to help, some to flee.
       Tsk. The moment has gone.
       [Go. Go!]
       He's sprinting again--a new surge of energy from somewhere. He vaults the park railings as if they're no more than half their actual height, and runs down another identical city backstreet. Running, running, running.
       [Don't let them catch you. Whatever happens, don't let them catch you.]
       The snitch sounds calm, though. Unworried.
       He hears a buzzing sound--and this time, it's not coming from inside his head. Civil protection drones, two of them, track his progress. One is close, maybe thirty feet above and behind, the other moving to scout ahead. These are observation-only, but stinger drones--taser-equipped and tooled up to take out a wide range of miscreants from bag snatchers to suicide bombers--won't be far away now.
       A pain pulses at the top of his neck, high up just underneath where bony skull starts. He reaches up and runs a finger over ridged scar tissue. The flesh there feels on fire. He wonders how those flames would look if he could see them. Would they have eyes?
       Down a main street, across a busy intersection, the traffic squirms and knots itself as he cuts through. The nearer drone drops lower, trying to get a facial ID. The harsh and high-pitched buzz of its rotors sets his teeth on edge. The scar on the back of his neck throbs.
       [Here.]
       He barrels into a metro station entrance, vaulting the ticket barriers, running full tilt down already-moving escalators.
       [Soon, soon.]
       A train waits at the platform, the doors all but closed and ready to depart.
       [This one.]
       He thrusts a couple of fingers between the rubber seals of the closing doors and shoves, creating enough of a gap to slip inside the carriage. Passengers shuffle away from him instinctively, creating a cocoon of space. He strides to the end of the compartment, itching with the need to keep moving. The connecting door is locked. They do that now, don't they? Frustrated, he slams a fist against the metal framework. Again and again, he pummels the metal frame yet curiously feels no pain.
       He hates feeling contained. Boxed in. Why doesn't the damn train move? And the lights are searingly bright in the carriage. Why do they have to be so bright? They're deep underground, and it should be dark.
       He lets himself slump to the floor, wanting to sink down through it, beneath the train, amongst the dirt and grime and the cold steel of the tracks. He'd like to listen to the clattering screech of the train growing fainter, watch its lights diminish until there is nothing left but him and the darkness. Impossible, of course.
       But the darkness comes for him anyway.

       It's a long way back from darkness into light. He feels a sense of anticipation, of arrival. An awakening of sorts.
       "Hey. Hey!" A slap across the cheeks, light but firm. He tries to react, to move, but paralysis grips him. Somebody turns his face towards a light so strong it makes his eyes water. When he tries to close them, fingers pry his eyelids apart. He feels a jolt of panic at his helplessness, this. . .violation. But strong arms pin down his body, and now a hiss like a spitting cobra sends a stinging sensation up his nostrils. A warm numbness spreads and spreads.
       Luca, he thinks.
       Of course.
       My name is Luca.
       Panic falls away to become just a tight little knot in the pit of his stomach. He sees faces peering down at him. Two of them. At least he thinks they're faces. Everything is blurry and out of focus.
       "Take it easy, pal," one of the faces says. "The relaxant will kick in soon enough. But you can talk to us. Let's start with your name, why don't we?"
       Cops. He's read about the powerful inhibitor sprays they carry these days. Better than being dropped by a taser, though. Or a bullet.
       "Luca," he mumbles. "Luca Perotti." His voice is such a weak, pathetic mumble he's not sure they've heard.
       A hand reaches behind, and the first cop touches the back of his neck lightly. "Yeah. Like I said. Chipped. Look, he's got the scar where they put the limiter in."
       The pressure eases on his arm. A different voice says, "So how come mister model citizen here's been acting so crazy? Aren't limiters supposed to stop all that?"
       "Beats me," Cop One says. "Rogueware infection, maybe?"
       "Don't be a jerk. Those things are unhackable. Military-grade, double-encrypted--all that shit. Once it's in you, you're gonna be on your best behavior no matter what. Won't even let you fart off-key if that's how it's programmed."
       "Jeez. It's creepy. You ever let them put one of those things in your head?"
       No one gives you a choice, Luca thinks. That's sort of the point.
       He doesn't like their smugness. Maybe he should let them see he can't be intimidated. Hey, you want to know something really funny? You're next in line! Chips to speed up reaction times. Chips with the latest watchlist updates and facial matching algorithms. Right there, snuggled up next to your posterior visual cortex. Or maybe a limiter chip that'll make sure your use of 'reasonable force' stays within legal parameters. Wonder how you'll like that?
       "What'd he say?"
       Luca tries to sit up . He's not on the train any longer. He can feel the cold cement of the platform seeping into his legs splayed out before him. He sends the signals out from his brain, but his body's not receiving.
       "So, Luca Perotti," Cop One says. "Want to tell me what's going on here?"
       Luca swallows and makes the effort to form words slowly. "I. . .don't remember. I was taking a break, getting some air. I work for a post-prod company, just off Dean Street. Graphic effects designer." The words come more easily than he expected.
       "Uh-uh." Second Cop shakes his head. He's staring at his hand-held. He must have done an iris scan before Luca properly regained his senses. "This says you're a war vet. Registered in a rehab program. History of PTSD-induced psychosis."
       "Told you." Cop One sounds vindicated. "That chip's a behavioral restraint version. Stops him from going bugshit if he gets a flashback. This ringing any bells, Luca?"
       Luca struggles to match these concepts with memories buried in the dark places of his brain, but he can't do it. There are too many shadows. The shadows creep through his mind, like a predator stalking prey in the long grass. Where the shadows have been, where the darkness has touched him, it's left behind a rawness as though his thoughts have an actual texture. Impossible though it sounds, they itch.
       "Am I in trouble?" Luca asks.
       "Depends what you've done, son."
       Cop One snorts. "You'll be fine. Specialist medics are on the way." The cop leans in. "Something's screwed with that behavioral limiter in your brain, but the head boffins will get you sorted." He chuckles. "You're kinda lucky, you know that? So long as you carry that chip, you're indemnified in law no matter what you do. Chip goes wrong, well that's not on you."
       Lucky? It's not the word Luca would choose. "I thought. . .there must be something wrong with me."
       Cop One grins. "Guess there was, or they wouldn't have stuck the chip in you. Nothing to worry about now, though."
       The inhibitor spray is still holding him in its grip. All he wants is to be able to stand up, get off this suffocating platform and back out into the fresh air. But something still doesn't feel right. Even with the sane part of his mind back in charge, there's something missing. Shadows jostle each other back there in the darkness.
       The medic arrives, a petite, Hispanic girl with scraped-back hair as dark as the voids within his brain.
       Cop One nods at her. "Hey, Penzo. How's it going?"
       She doesn't answer but dumps her medic's bag next to Luca and starts sorting through the contents. She doesn't look at him, not even when she swats his arm to raise a vein and, without consulting him, pushes a hypo needle into his flesh. It hurts, but she ignores his grimace. Moments later, he can feel the grip of the paralysis beginning to loosen.
       "Spill it," she says. She's talking to the cops.
       Cop One's tone sharpens up. "IC2 male, mid-twenties, found catatonic in a metro carriage. Linked to reports of street disturbances--a similarly described male showing mildly violent, psychotic behavior. Iris ID scan confirms the subject's a war vet chipped with a behavioral restraint. Looks like it's malfunctioned. Maybe picked up rogueware."
       Penzo passes some kind of scanner behind Luca's neck. "No," she says. "No chip."
       "What? Yes, there is. There's a scar--"
       "Doesn't mean the chip's still there," Penzo snaps. "Did either of you bother to check?"
       "But--"
       "You actually need me to tell you how to do your job?"
       Cop One falls silent, scowling. Now Penzo turns her attention to Luca. "Remember much about the last hour?"
       "A little. Some."
       "Any dizziness or pain? Strange feelings? Voices in your head? Flashing lights?"
       "A voice," Luca says.
       "Uh-huh. Tell me about the voice."
       "It was telling me what to do. Taking control. I couldn't shut it out! I had to do what it said!"
       "That's the chip," Cop One says, refusing to let it drop. "I told you. There has to be one. How else--" He shuts his mouth at Penzo's glare.
       "The voice, Luca. The one that tells you what you mustn't do? Or a different one? It's important. Try to remember, Luca."
       Why can't he remember? Darkness still circles inside his brain. Waiting. It's building into something, like a sneeze that can't be stopped or an itch that sooner or later just has to be scratched. The snitch had been real, hadn't it? The snitch made him do things. But wasn't it supposed to tell him all the things he shouldn't do?
       (Darkness. Waiting...)
       "Do you understand what's happened to you?" Penzo asks.
       Luca shakes his head.
       "Any of your buddies get injured back in that war? Lot of IED casualties, right? People losing an arm or a leg."
       "I don't remember any war," Luca says.
       "Sure, you do. You just don't want to. And I bet you've heard of phantom limb syndrome, too. A person gets a really intense sensation--a pricking pain or some kind of irritation that just has to be scratched. Only they can't because it's coming from a limb that's no longer there. They'll swear blind their ankle is itching fit to bust, but there's a big fat nothing below the knee joint where the blast caught it. No medical reason for it, just the brain playing a little trick."
       She waits to see if he's going to say anything, but Luca stays quiet.
       "Sounds like nothing, right? Nothing compared to the trauma of losing a limb, adapting to a new way of living. But sometimes, it's those phantom sensations that drive people to the edge of sanity. How do you scratch an itch that's impossible to reach?"
       Luca looks down at himself. "I haven't lost--"
       Penzo reaches behind him and runs a gloved finger up the ridge of the scar on his neck. It burns with sudden intensity. It's as though she's cutting deep into his flesh. "This. You've lost this. And now your brain is trying to compensate."
       Cop One looks more interested in Luca again. Cop Two's distracted, listening to something coming through on his earpiece. "You sure about this?" Cop One asks Penzo.
       "Are you sure you remembered to zip your fly this morning?" Penzo says.
       Penzo helps Luca to a sitting position, leaning him against the wall. They're still on the station platform. The distant rumble of an approaching train makes the platform tremble a little at its approach. "Where d'you get the extraction done? Some backstreet clinic?"
       "Illegal extraction?" Cop One says. "That's gotta be a five-stretch minimum, right there."
       Luca can feel pressure building. More than just the metro train approaching. A pressure inside his skull as well. An itch that needs scratching.
       [You didn't need that chip, Luca. They tricked you into thinking you did. You were just fine as you were.]
       The voice sounds very certain.
       "I didn't need the chip," he tells Penzo.
       "Uh-huh. Course you didn't. No one ever thinks they do."
       [She's lying. They're all lying.]
       "I'm okay now. Can I go, please?"
       "Luca. Look at me. Unauthorized chip extraction is a felony. And medically dangerous. There are side effects, mental trauma. You get me? Because what's the first thing anyone does when some kind of restraint is removed? You stretch out, flex aching muscles starved of stimulation. You scratch the itch. But what if you can't? What if the itch is coming from a phantom limb? Or, in your case, a chip that's no longer there. Then what?"
       Then there's no one else to blame. This is all me.
       Cop One has a nasty little smile on his face. "Looks like we may have to rethink that legal indemnity thing." He raises his voice to be heard above the clatter of the approaching train. "Maybe you're in a whole heap of trouble after all."
       "Jeez. Listen to this," Cop Two says. "Major blaze in progress a few streets away. Place called PixMotionPro. A video post-production company. Fire-crews at the scene say it's arson. Started in multiple locations. No word on casualties yet, but it looks bad."
       Everyone turns to look at Luca.
       Cop One's face turns ashen. "Whole heap of trouble," he repeats.
       The train is almost here, its headlight spearing out of the tunnel's darkness, driving it back. A discarded Starbucks cup skips and dances towards him along the platform, pushed by the plug of warm, fetid air driven by the train.
       [Just this one little itch. Then we stop. Won't that feel good?]
       But it won't stop.
       He can see that now.
       It will never stop. The sickness is still inside him, and even with another limiter implanted, it won't have gone away.
       Only one way he can end this.
       The single bright headlight of the train is splashing along the curved walls as it rattles into the station. Luca glances at the Starbucks cup that has almost reached them at the far end of the platform. It rolls left, then right, as if trying to come to a decision.
       The moving shadows inside his head part suddenly, like a patch of blue sky glimpsed through storm clouds.
       [Listen. Here's the deal.]
       And now he sees possibilities. Options. The cops are certain they have him neutralized. But run the sequence forward. The train's almost here. All he'd need to do is push away from the wall, fall onto the track just ahead of the train. If he lands right, if he finds his feet, if he can just keep ahead of the braking train, its carriages will fill the platform, plugging the tunnel while he runs on into the darkness. By the time they move the train, get the power turned off, he'll be long gone.
       Of if he lands wrong, falls across the track--
       If, if, if.
       [Feel that itch? Think how good it will feel to scratch it.]
       "Now I remember," he tells them, and they all lean in a little closer to catch his next words. Luca is half-sitting, half-squatting against the wall. He can launch himself from that position in the blink of an eye, now the inhibitor has all but worn off.
       The train clatters into the station at the far end of the platform, a one-eyed snake sweeping darkness before it. The momentary distraction is enough.
       [Go!]
       Luca is up and running again. The scar on the back of his neck burns fiercely, and it makes him think of flames. Flames that he still hasn't got quite right.
       But he will.
       And it feels so good to scratch the itch again.