The lights flickered overhead — a pulse that was barely noticeable, yet still grated. Gwen was looking down as she walked, to see less of it. The polished black of her shoes reflected in the off-white of the floor just as polished, and the rhythmic movement of one against the other calmed her mind a little.

Considering the circumstances, it had been a good enough day. She’d managed a decent amount of lab work, and now all the only task left was to set up the machines for the night before leaving. She should be glad, really — if only she could still remember how that was done.

Gwenllian was born long before the invasion, and had grown up in the soft, safe world that had been. Her memories of that time used to be strong, at first. But now, years into this changed reality, she could barely recall what it had all felt like — to walk outside without fear, to look up at the sun, to just stand by a tree and let the warm currents of air wash over… What it had been like to not have them everywhere, when you could step outside and not see every roof, every lamp post, every fence covered in their hated forms.

It seemed so unbelievable now that as a child she had actually liked birds.

The doors to the labs were all the same with the numbers taken off, and when she’d just started here it had been a challenge to memorize which was which; but Gwen learned soon enough, and by now could count them off without thinking. Stopping by her own door, she pressed her palm to the lock and waited as the machine processed it. A piercing light darted at eye level, making her flinch. This was a new precaution, and had reportedly cost a great deal, but no expense was to be spared when it came to vigilance — especially not here where such important work was being done. Gwen wished she could install something like this at home, too, but she had no hope of earning enough to afford it any time soon.

Not that they preyed too much on homes. In the beginning there had been a few incidents, but by now they must’ve figured out that was not where the threat came from. Yet it would only be a matter of time, Gwen was sure, before they arrived at the concept of blackmail; and then children would, of course, make the best hostages.

Gwen and Santiago took to driving Megan everywhere, and at night they would now all sleep in the same room, in the large bed they’d placed away from the window. The window was boarded up, of course, but they took no risks they could help. The school had its own security measures, too: windows also boarded, no excursions, no outdoor classes, and the number of guards increased threefold. Yet nothing was happening, and Gwen knew well that in absence of incidents control could lapse. And even if it didn’t, still any defense could be breached with enough cunning — the exact quality they had always been known for.

At last with a series of clicks and screeches the door slid open and Gwen entered, pulling it shut immediately after. She turned on the lights and watched as they settled in to flicker just like the ones out in the corridor. Presumably the entire building was afflicted.

The uncertain lights were the first indication that one of them had crept into the underground communications to force a breakdown. Right now, Gwen knew, the monitoring system would be searching for the intruder, but it was impossible to know if they would catch it in time. With the ever-increasing demand, the city services were getting sluggish. The plan had been that everyone would need to hold on for just a little while until a solution was found, and then all would go back to normal. The attacks were still rare enough that they could be ignored for the sake of the big picture, could be seen as a necessary sacrifice. The ‘little while’ extended to years, but for now things still held; and after all those years, all the searching, the answer had to be near.

Eliminating them was not hard on its own, but the trick was to do just that and no more. This was the task the government had set for people like Gwen, back in the beginning: to find a way to kill them, without killing anything else. The balance of life on Earth was too precarious after centuries of abuse, the environment not entirely healed; it was unacceptable to release a killing agent into it without being sure it would do what it was meant to, and only that. In theory, that should’ve been entirely possible — easy, even. They had all thought so, in the beginning.

To Gwen, the exuberance of those early days seemed silly in hindsight. At first, the talk had only been of who’d get it first — who would be the one to find the answer, be the savior of humankind and receive the glory and fame far beyond what could usually be expected in their profession. But as time went on and nothing happened, the enthusiasm faded; conversations changed, then died altogether, and where once the people had been looking for personal gain, now they were searching for the answer itself. Yet so far, nothing worked. There had been many times when it seemed they were almost there — when they created something or other that almost fulfilled the requirements; but each time, it failed the final, most rigorous tests, and they had to start again.

It couldn’t be long now before the public realized the science was failing them. The discontent was already there — little for now, but it would get worse. There were already rumblings that this had been the wrong choice, the wrong path, that there had to be a better way to cope with the invasion than to wait idly for the researchers to finally deliver what they had been promising. The researchers themselves were grumbling in turn, too — complaining about the standards being too high, the paperwork too much, the workload impossible. Gwen could feel the tension in the air, like a dam or a storm about to break. It would soon enough if the answer wasn’t found.

Gwen had been a rule-follower all her life, but no longer. She was not going to wait for the storm to come; she had chosen to do something about it. So far, nobody had found out — so far, she still had a chance.

The shimmering made her eyes hurt. Gwen gave up on the lights and turned them off, allowing the room to fall into semi-darkness. On a summer evening like this even a clouded sky provided a lot of light, but through the thick meshing on her window not much of it found its way in. Still, what little light did get through had a faint golden sheen, and she knew that beyond the clouds the sun was close to setting. She’d need to hurry if she were to get home before nightfall. In the dark, you could not see them come.

Gwen turned the machines on one by one, and the room gradually filled with noise. Just as she came to the last one, her phone rang.

‘Santiago,’ she said, putting him on speaker and laying the phone aside. The connection was clear, noiseless. ‘Home already?’

‘Yes,’ he said. ‘We had to rush, they were all over the school. But no attacks, not that I’ve heard of at least. Megan’s doing homework.’

‘Trying to,’ Megan called from a distance. She sounded normal, and Gwen relaxed a little.

It felt incongruous that such an ordinary thing as homework could still exist in their disturbed world. Then again, many things struck Gwen this way now. There were still shops, and libraries, and gyms; people still worked and went around on their business, keeping up the façade of normality because such was their way of life now — it was the expected behavior, the proper thing to do, and even if they had started to complain about it they were still doing it, at least for now. There was nothing normal, to Gwen’s view, in this sneaking about, in the way they all had to hide themselves away in their own city, avoiding the open streets, staying in at night. But if it helped preserve at least a semblance of order, it was better than nothing.

‘You coming soon?’ Santiago asked. ‘It’s near nightfall.’

He had no knowledge of what Gwen planned; she made sure of that. Her husband would need plausible deniability if things went wrong for her — not that she expected them to, with how careful she’d been, but it was best to be prepared. He might’ve guessed the truth, of course, or something close to it — he had seen her glued to her computer in the evenings, staying up well into the night. But when he asked she evaded, and soon enough he let her be. If questioned he’d have no need to lie, and Gwen did her best to keep it that way.

‘Almost done,’ she said. ‘I just need to get this started for the night, and then… Just a minute.’

Silent, he waited while she worked. The indicators began to pulse as she started the processes, lighting up one by one — all except the one she’d disabled, which if working would have alerted any of her colleagues who happened to enter that a connection was open. It had been surprisingly easy, really. She’d volunteered to install security updates, and used that chance to link her own computer to the machine at work. Now any results that the machine produced were dumped into her computer, allowing her to go on working after hours. Gwen had been praised recently on getting so much done; she knew her coordinators wouldn’t have been as laudatory if they looked into exactly how she’d managed.

It seemed harmless enough on the surface, but it was a breach of security, and Gwen knew that her punishment would be severe if she were caught. The longer she went on like this, the greater risk she ran, but if she succeeded… That was what she’d done it for — that was the whole point. If she found what they were all looking for thanks to this, the risk would be worth it. Everything would fall into place: they would be gone, life would revert to the way it had been, and her crime would be forgiven because of her service to society. If only she could find it…

Gwen finished setting up and leaned into the machine for the security check. As she fitted her forearm into the scanner and positioned her eyes before the panel, Santiago said —

‘What is that sound?’

‘New upgrade.’ The machine began its whirring and stuttering, and Gwen felt her arm being gently probed. ‘We’ve had another increase.’

‘Because of Far Cove?’

‘Yes.’

Just the name alone made the air seem a little colder. What happened at the Far Cove facility was not surprising, not really — of course they would figure out the concept of torture, that was only to be expected. They seemed to walk the same path Gwen’s own kind had, long ago — repeating the same mistakes, committing the same atrocities; but Gwen could feel no affinity with them, not when she’d learned the details of what happened at Far Cove. Some things were unforgivable.

The incident was mostly hushed up, but a little of it did trickle down to the public, only making people more alarmed. She never told Megan or Santiago of any details, yet they still knew enough to get nightmares, and Gwen avoided those herself only by working late and sleeping little. She abused caffeine and sleeping pills, medicating her body into compliance. If she worked hard enough, surely it would eventually pay off. The answer had to be out there. Perhaps it was something obvious, something they were all missing because it was too simple.

Sometimes, to try and force herself to continue, Gwen would imagine what it would be like when it finally happened. She pictured them dropping one by one, their black bodies on the ground with their feet up like dead cockroaches, seeming suddenly so small. When at last it happened, they would be helpless — betrayed by the very air that had been their greatest ally, powerless in the grip of the poison. They would learn the very last lesson they’d ever know, and then it would be over.

The scanner was moving over her arm sluggishly, reading the pattern of her veins, listening to her pulse. It would know if she were being forced; but while it would shut down in that case, it would not help her any. What happened to Far Cove could happen anywhere else, and Gwen was not sure she’d be strong enough to keep silent, like the people there had. The answer had to be found soon, before it was too late. The words beat in her mind like trapped pigeons, as she glared at the scanner, willing it too hurry, knowing it could not.

At last it made a happy beep, and Gwen pulled her arm out. The queue slid into work, and she straightened, rubbing her back.

‘Now I’m leaving,’ she announced, picking up her phone. ‘Let’s hope that maybe this time…’

‘You don’t sound hopeful.’

‘Well, because it’s never this time.’ She shrugged, then remembered he couldn’t see. ‘Still, we must hope. Hope and work. Eventually, it will have to…’

‘More work? Gwen, you’re hardly sleeping as it is.’

Gwen ignored that, saying instead —

‘Do you need anything on the way?’ She swapped the lab coat for the cardigan, not bothering with the buttons, then pulled the bag over her shoulder. The computer bumped heavily against her thigh.

‘No, we still have some of that chicken left. I’ll make soup.’

Gwen stepped out and shut the door, then had to wait as the lock processed her fingerprints and irises yet again.

‘If there’s any milk, I might —’

A deafening wail pierced the air, making her flinch and drop the phone.

Gwen hadn’t known how much louder the alarm sounded in the corridors. Instinct pushed her to cover her ears against the stabbing, nerve-tugging shriek, but she had to finish the scan if she didn’t want to trigger another alarm, now on her own door. She forced herself to stand still, as the sound drilled into her scull.

The wail ended just as the lights of the lock died.

‘— was that?’ Santiago was saying as she bent to pick up the phone. Gwen blinked furiously to shake off the afterimages.

‘Probably —’

The announcement drowned her attempt at an answer.

‘Evacuation,’ a deep artificial voice stated. ‘Three minutes to lockdown.’

‘Heard that?’ Gwen said towards the phone.

‘A drill?’

‘Guess so. I’ve got to go.’

‘Good luck.’

As Gwen’s vision cleared, she saw the flicker of the lights had gotten worse. Forcing an evacuation over that did seem a bit excessive — attacks on communications were nothing special by now, and most of the time resulted in nothing but a fried black-feathered corpse. Still, Gwen knew the facility’s control center believed a good drill could never go amiss. She tried to convince herself it was no more than that.

All around her, the doors were swinging open, emitting people — some in lab coats, others trying to change on the way.

‘Just started,’ the woman from the room opposite complained, when their eyes met. Gwen usually greeted her, but they never exchanged names. Closer friendships were not usually formed here, because of the nature of their work. ‘Night shift. Or was, I guess. Could you please hold my coffee?’

Gwen took the cup, and the two of them joined the current, walking rapidly while the woman pulled on a jumper and stuffed her lab coat into her bag.

‘Thanks,’ she said to Gwen, taking the coffee back. ‘Chilly evening. Perfect time for a drill.’ Her sarcasm was casual, only half-irritated.

‘It may not be a drill,’ Gwen said, for fairness’ sake.

‘Don’t,’ someone else muttered from her other side — another colleague that, to Gwen, was familiar but nameless. ‘I don’t even want to think about that.’

But Gwen had to wonder how many of them were doing just that — as they went to the elevators and past them, to the stairs and down, how many of them were asking the same question.

It had always been only a drill before. Sometime that luck had to run out. At Far Cove they’d thought it just a drill at first, too.

At first glance everyone around her looked normal, but it didn’t take much effort to see past that. Gwen caught the low rumble of voices, saw the widened eyes and trembling hands, and knew that they all were aware of it just as she was — of what they could do, and what that could lead to. The fear of pain and death was part of it, but only the surface; beyond it was a worse prospect still. In Far Cove, one of the employees had managed to wipe the system clean just moments before they got to it; she had been murdered for it, in a way so horrific Gwen refused to consider it, but she had saved the project. Such a chance might not come a second time. With all the security checks in place a breach was highly improbable, but with them you learned to expect just that. And if they got in…

They had to know what was being prepared against them — their attacks made no sense otherwise. But they knew no specifics of it, and as long as that remained true they’d find it hard to escape their eventual fate. However, once they did know… Nobody knew if they could read; nobody knew if they had any understanding of chemistry. Them knowing would be a variable too great to control. Everything would have to be reconsidered, redrafted, redone — and there was no time.

If they found out, they would probably win. And if they won, they would not tolerate humanity to remain. For all that they refused all attempts at communication, that they’d made clear enough.

The lights were still flickering. Gwen tried not to think, to concentrate on walking. Three minutes should be enough — she’d done it before. You had to walk fast, but if you did you could make it.

The walls of the stairwell were all windows on two sides — boarded shut now, of course, they resembled aquariums, with the boards showing through the dimness like large flat pieces of seaweed. The sound of steps reflected off the walls, multiplying into confusion. Gwen followed down with the others — it was only a few floors, only a handful of seconds, yet they stretched on, and increasingly she felt trapped here with all those people, doomed to walk in circles forever…

On the last step her foot slipped, and the spell broke. Someone caught her arm as she fell and pulled her back up.

‘Thanks…’ she tried to say, but whoever it was had already moved on.

The check-out gates were pinging incessantly as people streamed through them. Gwen let the crowd carry her, and in a few moments went through the gate and into the parking lot.

‘Seventy-five seconds to lockdown,’ the voice was saying. All around Gwen car doors were slamming, and one by one the engines purred awake. Frantically she dashed to her own car.

Inside, the wheel glimmered faintly in the semi-darkness. Gwen shoved her hand at the middle of it and, when it lit up and clasped her palm, at last relaxed a little. The car, at least, did not scan her eyes.

The initialization took thirty seconds; the engine needed five more, which meant Gwen would then have about half a minute left to make her turn and reach the exit. Many around her were already wheeling out — those who worked on the lower floors and had gotten down first — but that was, if anything, a good thing, because leaving among the last made it easier to maneuver through the place…

Something hit the side of her car, making her jump in fright.

‘Gwen!’

Ming was looking at her. With her one hand trapped by the wheel, Gwen used the other to wind down the window.

‘Give me a ride?’ he breathed out. ‘Mine broke down.’

Gwen pushed the back door open, and he slid inside, looking relieved.

‘Thanks,’ he said, still panting. ‘I tried to make it work, but the lockdown… I had to run. I can’t stay here for the night, I have to be…’

‘I get it.’

The authorization pinged complete, and Gwen started the engine.

‘It must be from yesterday’s,’ he went on. ‘Did I tell you?’

‘We haven’t seen each other, so I guess not.’

‘Right.’ His stare was a little unfocused. The engine roared to life, and Gwen began edging out of her space, careful not to graze the pillar. ‘I’m confused after work, I was right in the middle of… Anyway. They came after me yesterday, hard, I’m not sure what they… I had the car checked, but I think we were so distracted by the state the tires were in that we missed… I don’t know, something.’ He looked over his shoulder to where his car presumably was. ‘Please don’t explode.’

‘You should call them,’ Gwen said, meaning the control office of the facility. ‘Let them know they may have a problem here. They’ll check for you.’

‘Right,’ he said, still looking back.

Gwen and Ming had gone to the same school, but he was two years below her, and she hadn’t even known he existed until they were assigned to the same team at a chemistry competition. She had always felt the age gap, small though it was, and her instinct had always been to take care of him. She wondered sometimes how aware Ming himself was of it — whether he kept coming to her for help out of affection or calculation. Possibly it was both; regardless, she was not about to leave him behind. Gwen guessed they had meant only to scare Ming — he wouldn’t have been able to get away otherwise — but they had obviously succeeded, and she thought company would do good for him.

At last Gwen found her way to the exit lane, and sped out to the sound of ‘Twenty-five seconds to lockdown’. Ming reached over her to wind up her window, just as they were nearing the doorway. The heavy metal door had already begun its descent, the chains clanging as they unraveled. Outside, the yard seemed empty — Gwen couldn’t make out anything suspicious other than a few dots in the sky, and for a moment she hoped —

Then they were out the door and in the sudden sunlight, and there was someone running across her path.

Gwen swerved before she could think, and only then, in the rearview mirror, saw the tell-tale chameleon uniform — the heavy helmet — the soldier, aiming the net high and throwing, oblivious of the cars that passed him by close enough to touch. Then, like a trick picture that would only appear if you made your eyes see double, more soldiers showed up against the walls and ground — near-invisible in their uniforms that copied the colors of the sand and asphalt, and the grayish blocks the facility was made of. Gwen tried to keep to the exit lane, but it was impossible; she had to slow down to find her way in the mess of cars and people, and with her attention on it she didn’t immediately realize what the crowd meant.

The understanding hit about half-way. The low-hanging sun shone yellow, making everything seem warmer than it was, but Gwen suddenly broke into cold sweat. There was nothing drill-like about this. She could not see the sky directly overhead, and did not want to once she realized what had to be there. In the backseat Ming was silent, biting his lip so hard it had started to bleed. The car inched onwards, and Gwen’s hands felt slippery on the wheel. The soldiers ignored the ground, watching the sky only, moving where their job carried them without any regard for the vehicles. Civilians were expected to get out of the way on their own.

With a thud, something black hit Gwen’s windshield, making her yelp. Before she could make it out it slid down, and in a moment she felt it go under the wheel and crunch there with a wet, sickening sound.

Petrified, Gwen watched the outer gate move closer, their progress in the line slow as molasses but steady enough. She saw other cars get there and, once out, speed up and away, scuttling into the streets like ants into an anthill. The streets weren’t actually safe — nothing was safe that had no roof — but it was better than this. Anything had to be better than this, and Far Cove…

The second they were out of the gate, she floored it, and did not look back.

She flew through the deserted streets without any direction, intent strictly on getting away. Only when she saw the glimpse of the river to her side and realized how far she’d driven, she finally started to slow down, then at last stopped.

The sun had set, and the streets looked hazy in the pale blue of early dusk. A thin striped cat sat on the pavement, watching Gwen’s car. They ate cats sometimes, but not often enough to wipe out the strays. The air in the car suddenly felt stifling, and Gwen reached to wind down a window. Her hand was shaking so hard that at first she missed the button.

Ming met her eyes in the rearview mirror.

For a while they sat there in silence. His gaze shifted to her hands, and she clasped them together to keep the tremor down. At last, he said —

‘Gwen, I think I should take over.’

Wordlessly she crawled over to the backseat, giving him the front spot. Along with the rest of friends and family Ming was authorized to drive the car, and Gwen only half-listened as he logged himself in. She huddled in the back with her computer to her chest, and heard it ping softly in her embrace. The results from the lab must’ve come in — it was about time. But with Ming there, Gwen could not risk checking them. It would have to wait until later.

Ming circled away from the river and drove back, slow at first but then gathering speed again. The day was fading, but out of habit he did not turn on the headlights.

The buildings around gradually lost in height as they moved further away from the bank and into a residential area. From her place Gwen could see more and more roofs — pale steel, dim, empty. They were apparently not here — not on the roofs or the fences, not even in the treetops as far as Gwen could see when she leaned down to look upwards. It was tempting to think they had all converged on the facility and perished there, but she didn’t believe it. More likely, they were congregated temporarily elsewhere for their own, unfathomable reasons.