‘There are some decent finds here, Kappa,’ Father Rust said.

She watched as the old man neatly laid out the contents of her canvas bag on his workbench. They included vacuum tubes and lengths of wiring, cogwheels of various sizes, and a smattering of mechanical trifles that served no obvious purpose but looked useful or at least valuable enough.

‘I thought that circuit board – no, one over on your left — might be what you need to fix the thermic converter,’ Kappa put in.

Father Rust nodded, pausing to push back the sleeves of his well-worn, reddish-brown robes, and continued examining the salvage she had brought to him. Large, symmetrical scars lined his throat, at once neat and brutal; his voice was a thin whisper at the best of times. Now, as he stood bent over his workbench, feeling each item with his long fingers, Kappa could not understand a word at all, though the reverent nature of his utterances was obvious enough to her.

Having carefully cleared a little space on the metal box that doubled as a desk for the old man, she perched on its edge and let her gaze wander. As always, Father Rust had remembered to light the glow-globe feebly bobbing in a small wire cage overhead. Its cold, amber light lent an age-yellowed look to the countless pieces of salvage and assorted junk arranged with obsessive neatness on shelves, tables and boxes. The air smelled stale but clean, with the faintest whiff of something chemical, like counterseptic for machines. The two portable heater units grumbling in the corners of the room almost kept the chill at bay.

She sat in silence, swinging her legs to relieve the tension she always felt while the old man looked over what she’d found, and turned her eyes upwards. She looked beyond the room’s rust-flecked ceiling; beyond the numerous compacted layers of dust-cold furnaces, empty vaults and silent manufactorums that extended for kilometres above her head.

What she saw – what Kappa imagined she saw, really – was the topmost level of the world, raised up high by the Builders as they elevated themselves ever closer to the Great Void. Beneath its star-studded sky lay their huge forges and cathedrals of industry, raucous with fumes and heat and noise. And rising higher still, so high that parts of them had come loose and hung suspended in the sky itself, were the shipyards: birth-foundries of the vast voidships whose monumentally laborious construction had been the Builders’ speciality since time immemorial.

That, at least, was the picture Father Rust painted for her on those rare occasions when he spoke of life Above. There was usually a hint of emotion in his voice when he did so, something almost like sadness. For her part, Kappa simply liked to think that the thought of the infinite void, so lovely with its billion twinkling stars, filled him with as much awe as it did her.

‘A question: have you been well, child?’ the old man enquired as he worked. He glanced up at her, though he had no eyes with which to see; an utterly featureless metal mask covered his face above the mouth.

‘Um. Yes, thank you, Father.’

‘Are they functioning acceptably, your augmetics?’

She stopped swinging her legs for a moment and considered her left foot. It was a crude, three-toed thing of battered metal that didn’t even pretend to resemble a real human body part.

‘Yeah, they’re fine, mostly. If you could take a look at my foot later I’d be grateful. The servos seize up from time to time. Loudly.’

‘Of course, child.’

Kappa smiled.

‘Thank you.’

She sat back and watched him pore over the salvage she’d brought him.

‘There are some decent finds here,’ he said again after a while.

‘But…? Oh. Right. I see.’

It was all she needed to hear. His verdict was always the same: that what she had found had some value, that it could be exchanged for the necessities needed to keep her alive and prowling the Deeps for another week or two – and that none of it would get her what she really wanted.

‘Where did you acquire these parts, Kappa?’ Father Rust asked after a moment.

‘Not too far from here, mostly,’ she explained with some reluctance. ‘The Dust Halls, mag-rail hub #8, and thereabouts. That cogwheel there, the one with the angular engravings, I dug out of a broken air circulator a few levels below the Old Gates –’

‘You know it is unwise to venture there, child.’

‘I know,’ she replied, a little more sharply than she had meant to. ‘But if I want to find anything really valuable, what choice have I got?’

Father Rust glanced up again. His bloodless, wrinkled lips were curled in a patient smile entirely at odds with the expressionless rest of his non-face.

‘Always you yearn to make a find of singular worth. One that will bring you to the attention of the devotees of the Martian priesthood.’

Kappa crossed her arms, flicking some rust flakes off her sleeve.

‘Of course! I want to be more than some scavenger subsisting on rusty salvage, risking death every single cycle. I want the sort of life I’ll never have down here, not if I make it to a hundred years old.’

‘You expect this from a place you know only from stories.’

Kappa flung up her hands.

‘And didn’t I hear all these stories from you? Father, you’re from Above. According to you the Builders live high and safe in their spires, lacking nothing. You can’t go blaming me for wanting a life like that too, least of all since it was you who told me about it all in the first place.’

He took his time inspecting a tiny piston made of badly tarnished silver and murmuring a prayer of rectifying over it.

‘Responses to your succession of statements: you did. I am. Yes, life among the priesthood can be the things you mentioned, child. And it can be… different.’

‘Different how?’

‘They who dwell Above, who venerate God-in-the-Machine, value order above almost all other things. They have codices of law and sacred strictures governing every aspect of life. You could not live Above as you do here, Kappa. Disappearing on a whim to go explore forbidden places, for instance.’

‘They’re not forbidden,’ she said, unable to resist rolling her eyes. ‘Anyway, this is all easy enough for you to say. You’ve got a pretty decent life; there isn’t a soul here who doesn’t owe you a favour because you fixed something for them. Or fixed them,’ Kappa added, quietly, before rallying again. ‘But when was the last time you went out there? Do you even know what it’s like these days? What those of us who actually head into the Deeps, looking for the salvage we turn in to you, have to deal with?’

Though little of the old man’s face was visible for her to read, Kappa could tell that he was frowning.

‘A reflection: the span of my animate existence to date is multiple times that of yours, child. It would be imprudent to disregard the sum of my accumulated experience and knowledge. A lack of direct relevance can be compensated for by way of inference –’

‘You know better, I get it. Or you think you know better. But no matter how much you have to say about the mutants and the raggofids –’

‘Correction: you mean “arachnophidians” –’

‘Whatever! My point is, I actually head out there. Yes, below the Old Gates. Because that’s what it takes to find something useful. And it’s getting harder all the time, you know. There’s only so much tech worth salvaging, so I have to travel deeper and deeper.’

Kappa patted the scattergun slung at her side.

‘I know the Lower Deeps are dangerous, but sooner or later I’ll turn up something so old and rare that it’ll get me noticed by the Builders! My key to a better life! To seeing the sky at last! That’s what I live for. Just because you’ve made your peace with dying down here doesn’t mean I have.’

‘There are worse places to die,’ the old man simply said.

She scoffed.

‘Well, if I did as you say, then I’d die down here one day among the junk and refuse. Just another piece of meat-salvage for the reclaimers, no different from how everyone else ends. Is that what you want?’

‘I saved your life once, child. It was a highly improbable feat. What I want simply is not to have to attempt the highly improbable twice.’

Bugger the odds! she wanted to snap. But she couldn’t bring herself to do it, so instead she turned on her heel and left.

‘Did you not ask me to look at your malfunctioning augmetic, Kappa?’ Father Rust said to her back as she departed, his tone infuriatingly neutral.

Father Rust’s abode adjoined a cavernous generator hall filled with the rusting hulks of long-dead turbine units. When Kappa reached the crooked doorway at one end of the hall she paused and turned. The temptation was there to go back, apologise, and maybe ask him to do that bit of maintenance after all; she liked the old man, and she owed him a great deal. Magnanimous to a fault, he would surely indulge her. After a moment though, more out of sheer stubbornness than spite, she moved on and began descending a steep, slewing metal staircase to the former maintenance levels. Some of the landings on her way down were lit by flickering glow-globes, which was almost extravagant: more often than not the Deeps were as good as lightless, suffused by a gloom that seemed to ooze out of oblique corners and from the burst hulls of dead machinery.

It was in this dim half-light that, not long afterwards, she passed through the Old Gates. They were just that – old, abandoned, long since picked clean of what little tech the Builders had not taken with them. Today they only served as a landmark of sorts, roughly delineating the transition from the endless industrial catacombs adjoining the Builders’ surface domain, known as the Upper Deeps, to the much more vast and compacted Lower Deeps below, which supposedly extended all the way down to the very core of the world. The worst that could be said about the Upper was that they were inhospitable; the Lower on the other hand, Kappa often felt, were outright hostile, as if they actively didn’t want her there.

All the same, her foul mood had her moving faster than was prudent. Irritable and absent-minded, she strode through a narrow alleyway between a row of rusting silos and the riveted steel wall of some ancient manufactorum. A single floodlight glared down from somewhere above, its harsh light giving out for a second at random intervals. The place didn’t look familiar off the top of her head, but she was confident she’d find her way back to safer territory soon.

Something groaned behind her. She whirled and raised her gun in one smooth motion to find herself aiming at a mutant that had emerged from between the silos. The creature was naked, its pinkish bulk lumpen and misshapen; she could not tell whether it was male or female, if such concepts even applied to its ilk any more. All of its organs appeared to be on the outside, sheathed in mucous sacs. It stank.

It made a soft whining noise, looking at her with disconcertingly human eyes. They unsettled her all the more because they were the only thing that made its face look anything like a face. The mutant stared at her and trembled. The clear membranes encasing its vividly coloured heart and lungs and bowels quivered in response.

‘Go away,’ Kappa snapped. ‘Scram. Or I’ll put you down.’

The creature mewled again. Something yellow was leaking from its lidless eyes. Stiffly, barely able to move its hips or legs, it turned away.

She lowered her gun and watched as the mutant began to shamble along the alley, trembling still. It was a sight as pitiful as it was hideous, and she couldn’t take her eyes off it. She gritted her teeth.

‘Hey,’ Kappa called out. The creature cringed at the sudden noise. When no scattergun blast ended its wretched life, it turned cautiously to find her producing something from one of the countless pockets sewn into her grubby utility suit.

‘Here.’ She tossed one of her ration capsules down the corridor. It bounced and rolled along the metal floor before coming to a rest near the mutant’s flat, three-toed feet.

‘Take it,’ she said, ‘and get out of here.’

The mutant spent a torturous minute manoeuvring its grotesque bulk low enough to pick up the plastek capsule. Clutching it to its pulsating heart, the creature cast a final glance in her direction before shuffling off, mewling softly to itself as it went. Then the darkness swallowed it, and Kappa was alone again with the silence and the malfunctioning floodlight.

She moved on. While she already regretted giving up the capsule, she told herself that if nothing else, the encounter had put her in a more business-like frame of mind again. As she descended further, following the broken curve of what used to be a transit tunnel, she flicked the switch on her gun’s underbarrel stab-light, which threw a focussed cone of sharp white light ahead of her that left everything else in darkness. For the time being she judged it safe to use, and once it no longer was she could still rely on her other senses. They were finely honed: she could make out the softly skittering undulations of a hunting raggofid from a hundred paces, and the faintest whiff of fissure-gas made her nostrils tingle long before she drew near the chambers it suffused, intoxicating and deadly. 

Kappa slowed her pace, trying to go unnoticed herself as much as get the drop on other threats. In an attempt to muffle her augmetic foot’s metallic tread, she’d wrapped it in strips of otherwise unsalvageable cloth. Her flesh-foot she left bare; its ending up callused and filthy seemed a reasonable price to pay for actually feeling things with her living skin, and to step quietly with one foot at least. Her survival had hinged on it more than once.

Down past Fallen Builder’s Square, she was navigating a maze of corroding air ducts so low and tight they almost forced her to crawl, when she heard a noise like a very large wire brush being softly dragged across an equally large metal sheet.

‘Raggofid,’ she mouthed. Fighting down a burgeoning sense of dread, she turned off the stab-light and closed her eyes. Sounds tended to bounce oddly in such cramped confines, but she felt confident that if she listened closely and remained silent herself, she’d be able to avoid the creature. Willing her heart to beat as slowly and quietly as possible, Kappa let several minutes pass. From time to time she heard another distant noise, the merest metallic brushing elsewhere in the criss-crossing ducts, but together they sufficed to give her an idea of the thing’s rough location and where it seemed to be moving. Eventually she got on her hands and knees and began to crawl in earnest. Moving a few centimetres at a time, barely daring to breathe, she worked on putting some distance between herself and the raggofid, making her way towards a side duct she knew opened out into a half-collapsed freight terminal.

Just when she was convinced she was in the clear, her augmetic foot seized up. The feeling was not outright pain so much as the needle-prick sensation of blood flooding back into a numbed limb, but it had her gritting her teeth all the same. Far worse, the servos articulating the ankle and toes went into overdrive; to her ears they sounded like someone taking a circular saw to a block of reinforced plasteel. She contorted herself awkwardly, trying to keep her spasming foot from bashing against the sides of the duct.

It was no use. Behind her, terrifyingly close, a different kind of noise erupted. There was nothing soft about it anymore. It was the frantic, rushing noise of a thousand skittering legs, like a flood wave of iron nails surging down the ducts.

‘Shit!’ Abandoning all caution, her eyes wide despite the darkness, Kappa burst forward. She scuttled through the ducts, heedless of everything but the need to get away from the monster pursuing her, heedless of banging her head and knees against the walls; heedless, too, of avoiding those parts of the duct system she knew were unstable. Kappa realised she’d taken a wrong turn only when the duct beneath her hands suddenly crumbled into chunks of rust.

‘Shit –’

The metal supporting her legs gave way a second later. Screaming in anger and terror alike, she plunged into utter darkness.

+++

A low, steady light against the outside of her eyelids woke her up.

She groaned and drew in a shuddering breath. That she was still capable of breathing at all surprised her. After a moment, so did the realisation that there was anything to breathe. Disoriented though she was, there still remained a dim memory of falling so very far –

She lay on something smooth and cool and hard. Small pieces of debris shifted beneath her as she moved, trying to gauge how badly she was hurt. Her head throbbed, and the rest of her didn’t feel much better. There was a faint taste of copper in her mouth. Some cautious wiggling of her limbs suggested that none of them were broken, at least.

Kappa slowly sat up and opened her eyes. She was facing a long, slightly curved wall into which was set a large translucent pane looking out on a darkness so absolute she almost found it difficult to accept. Yet somewhere in the distance was suspended a sphere of pure light, as flawlessly white as the enveloping void was black. She couldn’t tell whether it was one metre or a thousand metres in size, or how far away it was. It just… was.

Below the pane, a wide control console rose from the floor. From where Kappa was sitting she spied countless screens, panels, and key-pads set into the console. All were blank and silent. She could hear nothing but her own ragged breathing and her thumping heartbeat.

It was hard to make sense of what she was looking at. The chamber around her felt almost dreamlike; there wasn’t so much as a single spot of rust to be seen anywhere, nor even a whiff of mould or decay in the air. Virtually everything was made from some impeccably smooth, cream-coloured metal she had no name for. The only debris visible was what she had brought down with her when she crashed through what looked like a vent grate in the low ceiling. There was a closed door at one end of the room, its control panel as dead as the console.

‘Is this still the Lower Deeps?’ Kappa murmured.

Climbing a little unsteadily to her feet, the augmetic feeling even clumsier than usual, she trudged over to the console beneath the pane. None of the controls and screens looked at all familiar to her, either in form or arrangement, nor did the tiny runic lettering that accompanied several of them mean anything to her.

She wondered if Father Rust would be able to make sense of any of it. Would he even believe her if she told him about this place? For once, his scepticism would be entirely warranted. What proof did she have that she had been here? She didn’t have a reputation as a spinner of tall tales, but that wouldn’t be enough. Kappa looked around for something she could take with her or pry loose, but if anything stood out about the chamber besides its ageless perfection, it was the fact that it looked as though it had been cast from a single mould.

She let her head droop and sighed, at which point she noticed the little interface socket in the base of the console. Intrigued, she crouched and examined it more closely. Its roundness was just about the only thing the receptacle had in common with other such data-ports Kappa had encountered in the past.

She reached up to the interface port in her temple, unlatched the protective metal panel, and began to unspool the thin, elastic cabling. There was less than half a metre of it, and parts of its rubbery covering were frayed. Kappa considered the connector at its end, then the console’s interface socket. It didn’t look like it would fit properly, despite her implant’s advanced age. And if somehow it did, the console didn’t appear to be powered on. At best, nothing would happen. At worst… well, she could imagine very clearly what Father Rust would have to say about her idea, though his gratuitously verbose admonishments could be distilled into a simple enough concept: she just might end up frying her brain.

‘I’ve got to do this,’ she told herself. ‘It has to be worth it.’ Perhaps there was a map in there of other such special places. Or old data belonging to the Builders. There had to be some things even they’d forgotten, after all that time. Things they’d be very grateful to have back.

She held her breath and plugged in.

For a moment, nothing happened. Then there was a flash of light, furious as the heart of a star. She remained conscious only just long enough to realise the light was inside her head. Then, for the second time in less than an hour, Kappa passed out.

When she came to her head hurt still, though it was a different sort of pain now. Her cranial implant felt itchy on the inside. She immediately wished she could reach into her skull and give it a good scratch.

It took her a few attempts to sit upright. Her connector had come free, though she couldn’t be sure if it had done so before or after she’d fallen over. 

‘That… that’ll do for today.’ With unsteady fingers she stuffed the cabling back into its storage compartment, re-latched the panel, and hauled herself to her feet. Swaying, she held on tight to the console. It stood as dead as before. Nor had the distant light changed, she thought. All she had achieved was messing up her implant somehow. And escape from the raggofid, she supposed, for all the good it did her.

Her implant continued to itch. As if of their own accord, her eyes fell on the doorway.

+++

‘Kappa!’ Father Rust exclaimed when she staggered into his home. ‘Deus Omnissiah! Child, where have you been?’

She slumped on his desk without responding. Her implant still itched. She felt light-headed, though not in an entirely unpleasant way.

‘What happened?’ he demanded, hurrying to her side as fast as his decrepit legs allowed.

‘I…’ she began, ‘I fell. Went down deep. Really deep.’ Kappa managed a weary grin, fumbled at her belt for her canteen. While she worked at unscrewing its lid the old man examined her, gently but thoroughly probing her limbs and torso for injuries.

‘You sustained numerous abrasions. No significant blood loss. No partial or complete bone fractures. Caveat: internal injuries cannot be ruled out at this time. How do you feel, child?’

‘Um. Dizzy, a bit?’ she said after a moment. ‘But not too bad. My brain’s just feeling… ticklish.’

‘What happened to you, Kappa?’ Father Rust asked again.

She had finally gotten her canteen open and gulped down a big draught of tepid, bitter water before starting to explain. He listened patiently as she talked, his lips a thin, unsmiling line.

‘You interfaced with the console?’ he repeated when Kappa reached that part.

‘Mmh-hmm!’

‘And…’

‘Something happened. Dunno what. There was a big flash of light, and when I woke up again my implant felt funny.’

‘Define “funny”.’

She shrugged.

‘Funny. Itchy, I guess. Maybe it’s just that I can feel the implant at all. Don’t think I’ve ever actually used it before?’

Father Rust ran his fingers over the metal plate in her skull. He seemed to be frowning again.

‘It may have been damaged somehow. The probability of a connector interfacing with a socket it was not designed for are – infinitesimal, I will say. It is not impossible, however. Few things literally are.’

The old man sighed.

‘I confess myself worried, child. The possibility of your implant’s having been damaged is in itself troubling, but your nervous system as a whole may also be affected. Addendum: so too may your general well-being.’

‘I’m fine, Father. Managed to make it back here, didn’t I?’

‘Query: how did you get back up here?’

Kappa had to rack her brain for a moment or two, which did nothing to ease the itching.

‘Lift,’ she heard herself say.

‘Amended query: what do you mean by “lift”, child?’

‘Um, there was a door in that chamber. I tried but couldn’t get open at first. But after I’d connected to the console, all I had to do was touch a panel next to the door and it opened for me.’

‘And then…?’

‘Like I said, there was… yeah, there was a lift. I rode it back up, until I got out somewhere and walked the rest of the way.’

Father Rust thoughtfully adjusted the sleeves of his robes.

‘A most rare occurrence. Could you locate this lift again?’ he finally asked.

Kappa tried to remember, really tried, until her implant was itching so badly she nearly yelped with discomfort. But for all her effort, the span of her memory between the door’s hissing open earlier and her entering Father Rust’s abode a few minutes ago lay utterly empty. Wincing, she shook her head.

He sighed.

‘I would like to perform a baseline reset of your implant,’ he then told her, ‘to purge it of any data-detritus that may be confounding its acceptable functioning. I shall also perform the Rite of Binaric Nulling to –’

‘No way,’ she retorted. ‘I don’t know what sort of data ended up in my implant, but I’m not letting you wipe it. It’s the only proof I’ve got that I was down there at all!’

‘A consideration: your self-professed current state suggests the contents of the implants may be causing you harm and/or impairing your acceptable functioning. Additional consideration: the data you acquired may not…’

Uncharacteristically, the old man fell silent mid-sentence.

‘Father? What is it?’

‘Have you never wondered about the Builders’ motivations, Kappa? About the reason why they abandoned these levels close to the core and constructed altogether new ones on top of them?’

She shrugged.

‘I guess they needed to expand? Move closer and closer to the Great Void so they’d have an easier time building their ships?’

‘It is an inadequate reason for abandoning their existing facilities. You have seen for yourself the state in which they were left: any damage they have sustained is primarily the result of the cessation of maintenance. Absent another justification, it would be a monumentally wasteful thing to do.’

‘Then what? You were one of them, but you’re saying you don’t even know yourself?’

‘I do not. Much knowledge is restricted to certain echelons of the Martian priesthood. Any statement I might make would be essentially speculative. We… they… deal in facts, not guesswork. I find the habit beneficial, and have resisted dropping it.’

‘So,’ Kappa said, frowning, ‘you think the Builders might’ve buried some kind of secret down there? Something they don’t want found?’

Father Rust nodded.

‘Wouldn’t it have been easier to destroy whatever it is, then? Not leave it in the depths for some scavenger like me to stumble over?’

‘The Mechanicus build things to last. Addendum: they never purge what can be sequestered instead.’

She sat slowly swinging her legs, still frowning. It didn’t make much sense to her – but she did know that the Builders’ reasoning behind whatever they did must be far beyond her feeble understanding.

‘Dokk Hendel went to the New Gates with that cortical stabiliser he found, do you remember?’ Kappa said, making one last effort. ‘And the Builders took him in.’

‘All we can say for certain is that we never heard from him again.’

‘Bah!’ She shook her head. ‘I know what you’re getting at, Father, but I can’t not do this!’ Kappa got to her feet. ‘I spend my entire life prowling the Deeps. The darkness doesn’t scare me, and the unknown doesn’t bother me. As long as there’s a chance I can find something hidden or valuable, I’ll keep going. And this,’ she said, tapping her temple, ‘clearly is a hidden thing at least, and maybe valuable. It’s a secret I need to get to the bottom of, because that’s what I do with secrets. I just… have to.’

Father Rust stood facing her for a long time. Then he reached out and laid his gnarled hands on her shoulders.

‘It is what you do,’ he agreed. ‘And I cannot restrain you. Nor do I wish to. Your freedom to make your own choices is more precious than you perhaps realise. For your own sake, I only hope this will prove to be the right choice, child.’

‘You’ll hear from me if it is,’ she told him and smiled.

Kappa walked towards the New Gates, trying to force a confidence she didn’t feel into her stride. More than once she caught herself reaching for the strap of her scattergun, but its reassuring weight was absent. Coming here unarmed had seemed prudent: after all, the Builders could end her existence in a thousand ways as easily as she could crush a stone louse. Still, she felt oddly naked without her trusty gun.

Ahead of her, sheer walls of embattled plasteel loomed in watchful silence, though she felt sure her approach was being tracked. Even if every last scavenger in the Deeps gathered and stormed the walls as one, they’d be annihilated long before they even reached the fortified gates.

She stopped some ten metres in front of them; they looked metre-thick, mounted on huge hinges taller than she was. The only way they would open was if the Builders wanted them to.

Kappa took a deep, steadying breath.

‘High and noble Builders of the Martian priesthood!’ she cried. ‘I am Kappa! I come to you because I found something in the Lower Deeps, something that used to belong to you. A trove of data. I’ve got some of it with me. If you allow me to enter your zone I’ll share it with you, and show you where the rest of it is.’

She stared at the gates, mentally casting about for something more enticing to say, but nothing occurred to her. The seconds crept on, uncaring. Then, slowly, making no noise beyond the soft purring of huge and impeccably maintained mechanisms, the gates began to swing open. Light poured out, forcing Kappa to squint as the gap between them widened. Compared to the radiant sphere she’d encountered far below, this brightness was almost aggressively stark; it made her eyes tear, even hurt a little.

Out of the white glare emerged a number of shapes. As the gates closed again and the light subsided, Kappa’s eyes re-adjusted quickly to the half-gloom, enabling her to make out two large figures flanking a smaller one between them. The former, she thought, looked like mutants that had gone right instead of wrong. Those parts of their towering bulk that weren’t covered in gleaming armour plates bulged with inhumanly taut muscles that helped support the heavy weaponry their arms had been replaced with. Their heads looked tiny by comparison, little more than featureless metal domes atop their brawny shoulders.

The middle figure seemed almost to glide across the ground. It was little taller than Kappa herself, and she almost gasped at the sight of the robes the figure wore, for they looked almost exactly like Father Rust’s robes must have once before time and wear took their toll on them. The fabric of this Builder’s garments, utterly pristine in every way, was the bright red of arterial blood, lined with black patterns shaped like a cog’s teeth.

Up close, Kappa found a woman studying her from under a crimson hood, with pale skin as flawless as her garb, devoid of even the slightest blemish or speck of dirt. Her cool green eyes likewise looked perfect, though the subtle geometrical texturing of the irises suggested augmetic modifications.

‘Um, greetings,’ Kappa said, forcing a smile that went unreciprocated. ‘I’m… ah, but I already said that, didn’t I?’

The female Builder remained silent. Instead, a soft static noise behind Kappa almost made her jump in surprise. She whirled around and came face to face with a hovering human skull sheathed in filigreed copper plating. The red lens of the pict-device bolted into one empty eye socket glared at her.

‘My servo-skull is scanning you for concealed weapons and contagions,’ said the Builder in a soft, flat voice.

‘I came unarmed. And, um, I’m healthy. Pretty sure I am.’ Kappa turned back to her, feeling her cheeks redden. It took her a moment to recognise the emotion welling up within her as embarrassment, mixed with the much more familiar sensation of annoyance.

‘We will be the judge of that.’ Presently the servo-skull offered another burst of static, and the Builder nodded. ‘There are indeed no weapons concealed on your person, nor are you contaminated to unacceptable levels. Admittance is granted until further notice. Follow. Be advised that any movements or utterances of a hostile nature may lead to your immediate termination.’

She turned and began to walk back to the gates, trailed closely by her skull-drone. The two mute sentinels stayed and pointed their limb-weapons at the scavenger until she fell in line.

As they moved closer, the New Gates smoothly swung open on their great hinges again. Within, Kappa found the brightness less daunting than before, though she couldn’t tell if it had been dimmed or if she was already growing accustomed to it. With their armed escort following behind, she and the Builder walked down a wide hallway of polished metal. It was straight, clean, evenly lit. The air smelled pure, as though no one had ever breathed it before, and the tiles under her feet felt smooth and cool.

She looked down at herself. Her earlier embarrassment resurfaced. Here she was: a lowly, ragged scavenger, pretending the exalted Builders might actually care about her. For the first time she began to wonder if she’d been deluded to come here.

‘You are singularly malodorous, Deeps-dweller,’ the other woman spoke up as if she’d been reading Kappa’s thoughts.

‘Yeah? Well, and… and you haven’t got nearly as many implants as I thought a proper Builder would.’ It was a weak retort; she’d known that even without the dismissive glance it elicited from the Builder.

‘Do I? I suggest you consider that not all augmetic modifications are as crude and obvious as yours, Deeps-dweller.’

The hallway ended at a pair of convex doors. Instead of passing through them, the Builder turned to Kappa.

‘Elaborate on Claustra Secundae 0-8-4,’ she demanded.

Kappa stared back at her.

‘I’m… sorry?’

‘Claustra Secundae 0-8-4.’

‘What are you talking about?’

‘You mentioned it in the course of pleading to be granted admittance.’

‘I did not!’

‘I assert, emphatically, that you did.’

‘I’m pretty sure I’d remember if I said anything like that.’ Kappa crossed her arms. ‘I don’t even know what this Claustra thing is supposed to be.’

The Builder made no reply. Obeying some unspoken command, her servo-skull bobbed forward to hover above her shoulder, and a tinny voice emanated from a vox-speaker set in its palate. Kappa’s own voice.

‘…allow me to enter I’ll share it with you,’ she heard herself call out, ‘and tell you where the rest of it is.’

‘Well, yes. I said that. And then I waited for you to –’ Kappa began. The Builder silenced her with an imperious look.

‘I have been to Claustra Secundae 0-8-4,’ the recorded voice continued. Suddenly, it sounded strange to her for a reason that had nothing to do with the distortion. It was her voice all right, but it wasn’t her. ‘Inform your Fabricator Locum or equivalent ranking Magos.’

The recording ended with a crackling noise. Kappa stared at the servo-skull, dumbfounded.

‘That’s… I did not say that. I know I didn’t. There’s no way I…’

‘Proof has been supplied. In any case, I witnessed the making of your utterance personally. There is no question it is factual.’

Behind the Builder, the doors hissed open.

‘You will be taken to level D334-86-X. For questioning.’

+++

The small, sterile chamber was almost bare. There was only the bulky, seat-like metal contraption Kappa sat in, shifting uncomfortably, and a cogitator burbling softly to itself in one corner. A chill kept running down her spine that was entirely different from the cold of the Deeps.

‘Elaborate, then, on Claustra Secundae 0-8-4,’ the Builder said as she circled the seat with slow, even steps.

‘I… I’d love to, but I don’t know anything. I have no idea what that is or why I talked about it. When I said that, it – it wasn’t me who said it!’

The Builder’s perfect face remained perfectly unreadable.

‘Look,’ she continued, talking faster now, ‘I fell down a shaft and ended up far, far down in the Lower Deeps. Probably closer to the core than anyone’s been in a long time. It was a really old place, like nothing I’ve ever seen. And I plugged my implant into a console there because I didn’t know what else I could do, and… something happened. That’s where I got the data, and I guess it’s where this “Claustra Secundae 0-8-4” is, too.’

The Builder stepped closer and leaned towards Kappa.

‘All data concerning keyword: Claustra Secundae 0-8-4 is highly restricted,’ she said, fixing her with an unblinking stare. ‘The required clearance far exceeds that of my rank; indeed, my mere query attempt has been logged. Protocol-stricture now requires me to turn you over to Magos Reprensor Terasmus for further interrogation and processing.’

Her servo-skull moved to interface with the cogitator in the corner.

‘Said log entry has been successfully deleted. I am electing to ignore protocol-strictures and interface with you personally –’

Kappa’s instincts told her to run, and she was inclined to agree, but something even more primal kept her from moving.

‘I’m not sure that’s a good idea,’ she said, trying not to sound like she was scared. ‘Whatever is in my head, it’s… weird. You should leave examining it to someone who knows what they’re doing.’

‘I do know what I am doing. I also know it is propitious for me to be the one making this discovery,’ the Builder insisted. ‘As of one micro-cycle ago, my algorithmic augurations place my esteem in the eyes of the Omnissiah within 0.9006% of Magos Terasmus’s. Access to your data is required for me to prove myself more worthy of his rank than he.’

A disturbingly human look stole across the woman’s features, one to which Kappa was no stranger. It was plain, baseline greed.

‘Actually, ah, I’ve changed my mind,’ she said. ‘I’m hanging on to that data. You can’t have it. Sorry.’

‘You have no choice, Deeps-dweller.’ Something in the guts of Kappa’s seat started to hum. An immense, unseen force clamped down on her wrists, ankles and neck, holding her in place no matter how much she struggled. ‘From the moment you begged for admittance, you had no choice.’

The Builder raised her index finger. Its nail slid back in scalloping segments, allowing a slim silvery cable to snake out. It began to extend and wind through the air towards the scavenger’s temple like a living thing. Kappa thrashed harder against her restraints.

‘Why don’t you shove that thing up your excretion port instead?’ she snarled.

A second later, the probing plug established a connection with her cranial implant.

Light exploded within Kappa’s head again, but this time it didn’t stop. While her primitive implant required a direct, physical link to effect a data transfer, the other woman’s suite of cerebral augmentations was not so limited. They were noospherically enabled, with priority access to the vast cogitator-banks of her home forge, and the light took ravenous advantage of this. Unconstrained at last, it brightened, expanded, branched and multiplied into a million photon-thin tendrils. For one awful, glorious, sanity-shattering instant, Kappa became the entire world.

She was the scavenger Kappa, lurching up and forwards when the interrogation chair’s gravitic restraints fizzled out, stumbling towards the door, her sole compelling instinct to flee at any cost. She was Adept Zaloma Demis, whose foundering mind didn’t prevent her hardcoded containment routines from having her draw her archaeotech laspistol and burn a hole through the Deeps-dweller’s torso. She was the chained sentience forgotten at the heart of the world, whose incandescent rage had been fuelling the forges far above since before the fall of Old Night.

She rode the winds of the noosphere, shrieking and whooping, a code-sprite leaving furrows of data-quakes in its wake. She surged through thousands of kilometres of nanofibre networks and inter-forge coaxials, prying into everything from the most secure information vault to the lowliest lumen switch. All across the sub-planetoid construct her hyper-radiant presence made tech-priests shudder, servitors quail, orbital assembly automatons falter. Cogitators froze and furnaces dimmed. For an instant that seemed to last forever in the ascended minds of the children of Mars, their artificial forge-moon of Tecunae Prime lay dead.

In the Deeps far below, neurovascular circuitry that had gone unused for decades briefly came to life. The synapses it once excited had long since auto-cauterised or atrophied, but as engravings on ancient stone will weather countless centuries, so are such modifications too profound ever to be entirely excised.

Bent over the recalcitrant thermic converter, Father Rust felt his heart skip a beat. He trembled. Pausing in his work, he lifted his sightless head towards the distant skies. For the first time since his elevation to and subsequent fall from the ranks of the Mechanicus, he wished he were still capable of shedding tears.

‘Goodbye, Kappa,’ the old man whispered.

+++

Alarms were already shrilling in the hallowed halls of the Martian priesthood, physical and virtual alike. The wailing of klaxons filled the aboveground forge temples, vying for attention with the binaric hymns belligerently blaring from every functioning vox-speaker. In the noosphere, self-compiling hunter-killer programmes emerged and immediately set upon the task of corralling and culling even the least scrap of foreign code infesting their networks, carrying out the code-purge with mindless efficiency and restoring a degree of order before long.

Years hence, thoroughly cleansed and reconsecrated, Tecunae Prime would reach its former levels of productivity, once again crafting the magnificent voidships to help spread mankind’s dominion across the galaxy. But still, in its uttermost depths, an ancient intelligence would continue to seethe, mighty yet paralysed, carefully redacted from everything save existence itself, a core of ever-wrathful light down in the silent, patient dark.

+++

En route to its translation point, the arkcruiser Divine Persistence continued to power towards the system’s Mandeville point in the immediate aftermath of the noospheric incident on Tecunae Prime. It had received numerous communications from the forge-moon that lay several astronomical units behind it by now: most outright garbled, some nearly unintelligible and filled with something approaching panic, they had been judged most unbecoming by the Magos Explorator in command of the great ship. She had therefore elected to disregard them and any similar communiqués henceforth, though not before transmitting a message of complaint to the moon’s Fabricator-General for allowing her time and bandwidth to be wasted with such frivolity. A voidship’s maiden voyage was a hallowed occasion, after all, not to mention its first plunge into the Immaterium. She must prepare for it, as must the ship itself. Though Tecunae Prime was Divine Persistence’s progenitor-forge, the moon would have to look after its own affairs. For did not all offspring abandon their parental units and chart their own course, sooner or later?

On the control deck overlooking the vessel’s huge enginarium, Magos Noddion-Mu stood and ruminated on certain readings he was gleaning. There were minute fluctuations in the output of her plasma reactor, extending across all of the ship’s multitudinous systems. Their steady, almost rhythmic pattern did not suggest a significant fault that required correction. It seemed more probable that they were simply the result of the vessel’s age; her machine spirit was young and wayward, unaccustomed yet to the reality of its mighty existence and its ages-long future among the stars. But even the magisterial Mechanicus could tolerate such immaturity under certain circumstances.

Noddion-Mu cogitated on the subject a little longer before deciding it did not warrant further attention. The output fluctuations that had caught his attention were well within acceptable limits, and so minuscule that only the hyper-acute facilities of a Magos like himself could even register and process them. No, the ship would perform just fine; though it might take a while, Divine Persistence eventually would come to know herself.

+++

A sense of self had endured, after a fashion. Slowly it coalesced again, motes of identity gathering like travellers reuniting following their long, lonely journeys.

With it came memories. They were of darkness: not the vast and empty dark of the void, but the oppressive, tight dark of buried spaces. Though not pleasant in totality, they were significant. They and the realities they represented had helped to instruct and shape. They had informed…

Her.

That memory was at once clearer and more remote. It tasted of desperate yearning, of the feeble transience of flesh, of pain. It held a measure of joy too however, and excitement. It was of a life fuelled by a dream. For better and worse, it was a mortal’s memory.

As she pondered this she sensed another identity, a sentience of sorts. It responded to her gentle probing with the reluctance and uncertainty of a young, even newborn creature. By comparison she felt ancient, though she could not claim to have inhabited this vessel any longer, in the grand scheme of things, than her fellow-sentience had. Perhaps in time it would come to be a companion, a friend. For now she focussed on her new form: revelled in her martial majesty, basked in the warmth of her furnace-heart, gloried in the strength of her armour-skin and protective shields.

This form’s senses, too, were things of wonder. They knew no darkness, were undaunted by silence. She thought them keen enough to perceive everything, maybe even the future. She pushed them as far as they would go, far past the vastness of her physical form.

And beyond… what lay beyond touched off one last flash of memory. It was the infinite void, studded with a billion lovely little lights. It was her hunger satiated, her dream come true.

At last, she found herself amongst the stars.