Day and Night were little more than abstract concepts within the depths of a Hive City. In the Lower City, far from the light of the sun, the streets were illuminated by great lights suspended from the ceiling that only served to accentuate the shadows of the warren of alleyways that branched off the thoroughfares. In the better off areas these lights would dim and brighten in sync with the rising and falling of the sun, but the business of the hive would not stop for something as insignificant as night. The lower city was therefore kept constantly illuminated, save for areas that have fallen into neglect or disrepair, so that the ever-present enforcers may keep some semblance of order and the people may work around the clock through the clever use of shifts. The prize possession of each family would often be a small clock by which they could measure the passing of hours, and periodic hymnals broadcast over the public tannoy served to remind the workforce when it was time to work, pray or sleep. In the Underhive, even the concept of time had been corrupted. This far down, the people lived in perpetual twilight and timepieces were the preserve of only the wealthiest of chieftains. Most underhivers simply rose and slept according to the needs of their own body.

And so it was that when Amelia awoke, prompted by a buzzer built into her wristwatch, she found her room lit by the same mesmerising patterns of light from the waterfall. The sound of the mutants and humans of Waterfall going about their daily business seemed largely unchanged from the night before. As she stared out of her window, she was greeted by the same kaleidoscopic shape of the great waterfall at the centre of the town as it refracted the town’s light back upon its streets. For the Underhive, no time seemed to have passed whatsoever.

In this, the Overhang was an oddity, being a favourite of lower-hive mercenaries, and through its thin walls Amelia could hear the sounds of the tavern’s other patrons waking, while the smell of sizzling meats wafted up from the ground floor. The Overhang hosted a number of amenities that were rare in the undercity, such as double glazed windows that meant its more delicate customers could go without rebreathers, or the salvaged boilers that provided Amelia with the hot water in which she was gleefully washing away all the grime that she had gathered on her journey this far. It was largely a futile effort, she would inevitably have to put on the same dirty clothes as yesterday, but the psychological benefits were immeasurable.

As she washed her hair in the sink, having taken care to avoid getting any of the machinery of her psychic hood wet, she sensed the diminutive mind of Luka moving about on the other side of the door. When she emerged, she saw the girl staring with childlike wonder at the double headed eagle engraved onto Amelia’s breastplate. Luka turned at the sound of the door opening, only to have her eyes widen in horror at the nest of wires that emerged from the back of Amelia’s skull. There was something funny about this mutant, whose deformities would have horrified anyone on the surface, being so terrified at what was, by Imperial standards, rather tame modification and Amelia stifled a grin as she slipped on her shirt and trousers, before turning her best piercing stare on the small child.

‘Why didn’t you run?’ Amelia asked, curiosity keeping her from simply lifting the answers from the child’s head.

‘You’d find me, kill me.’ Her fear was so honest, so heartfelt, that Amelia saw herself for a brief moment as the ruthless leader of glowing eyed demons that had been Luka’s first impression of her.

‘Not if you killed me in my sleep, I know you have a knife.’ Luka’s hand moved automatically to the fold in her ragged clothing where she had secreted the small shiv and she fell silent, her eyes downcast.

‘I’ve nowhere else to go.’ The words came out in a near-silent whisper, as if it was a statement she was unwilling to confront.

‘You killed my clan; I can’t survive on my own. I’d be killed by demons or end up slave to a weaker master. I don’t know your clan,’ she gestured towards the double headed eagle on Amelia’s armour, ‘but you’re strong, and you haven’t killed me or sold me off.’

Amelia paused, and rested her hand on top of the Aquila.

‘You’ve never seen this symbol before?’ She was incredulous, it was impossible for anyone to have never heard of the Imperium. Some of her shocked disbelief must have slipped into her tone, because Luka cringed back, her spines scraping across the floor.

‘I’m sorry!’ She shouted in desperation. ‘We lived in the Wall; we never saw the clans that lived on the other side! We’d never attack if we knew!’

‘You’ve never heard of the Imperium?’

As Luka frantically shook her head from side to side, Amelia came to a revelation. This far down, there was no Imperium. If these people knew of the Imperium in any way then it would be in the realm of myth and legends. Even in the lower hive allegiance to your local gang would be far more relevant to the population than the Imperium.

‘Who do you worship?’

There must be some element of the Imperium that existed even this far down. Luka shuffled backwards again and Amelia realised she had hit upon some secret. Still, she needed to be sure.

‘If you don’t tell me, then I will take the information from your mind.’

‘God,’ came the sheepish whisper.

‘And who is God?’ Amelia’s words were laced with psychic energies to compel her to speak.

‘Grandma came down from the land above, where the Demons live. She told ma about God, and ma told me. God built the hive and everything in it, he sits at the top and rules over everyone. If you pray to God then he might give you wishes, ma said that God forgot about the Undercity, but that as long as I have my necklace God will listen to me.’

With trembling fingers, she drew a delicate chain from her collar, clutching the pendant in a closed fist as if she was drawing strength from it before reluctantly opening her hand and offering it to Amelia. An Iberian Crown rested in her hand, an imitation gold coin that would have been worth a month’s wages within the hive but was utterly worthless this far down. Worthless, except for the face of the Emperor rendered in profile on one side of the coin. Only psykers truly understand that faith has its own presence in the warp, and to Amelia’s eyes it seemed this simple coin held more of her attention than it should. It was not faith as she knew it, with grand temples and massed devotions, and it was twisted subtly by Luka’s mutations, but it was still there, an earnest and heartfelt belief.

‘The rest of the tribe laughed at us,’ Luka continued, ‘they said God didn’t care about us, that there were no gods, just steel and the strength of men’s arms.’

‘They’re right,’ Amelia interjected, ‘but not in the way you think. I know your God, and I serve him. He is the Emperor of all Mankind, and the ruler of this Hive, and countless others. Every human is counted amongst his subjects together in the Imperium,’ here she again rested her hand on the aquila, ‘larger and more powerful than any clan, than every clan.’

‘The Emperor didn’t abandon the people of the Undercity, they turned away from him. He believes that all humanity should be united to a common goal, but instead your people chose to reject his message and to seek their own power without caring for the damage they cause.’

Luka was watching Amelia like she was a tribal shaman imparting ancient wisdom, and Amelia decided that she should use this newfound awe.

‘That is why people down here become mutants, they’ve spent too long away from His light and have become corrupt because of it. The Emperor can’t take your mutation away, but if you serve him then you can work towards forgiveness for the crimes of your ancestors.’

There was some part of Amelia that hated toying with her emotions like this. She was no stranger to psychological guilt meant to instil loyalty and it felt somehow wrong to use the same tactics on someone else, especially a child. There was something incredibly tragic about the way Luka’s lips pursed together as her face took on a look of steely determination. Still, Amelia had to believe she had done the right thing. On a philosophical level, Luka would have spent her life lost in the underhive, never even having heard of the Imperium. Amelia was giving her hope in this hopeless place, and validating faith that was so rare amongst her kind. She would have also been hypocritical not to deny the practical benefits; this place was alien to Amelia, and to her retinue, and she needed a guide familiar with the local area who was bound to her by loyalty. She had positioned herself as an agent of Luka’s faith, and she could see with tragic certainty that the child’s mind was now wholeheartedly devoted to her.

As Amelia set about buckling on her breastplate, she was surprised to see Luka holding out her Stormcoat and the ragged cloak she had used as a disguise. Unnerved, she thanked the child and went quickly to the main hall of Overhang, where she breakfasted with Helena and Al’Said on some manner of fried meat that was almost, but not quite, recognisable. As they went out into the streets of Waterfall, Amelia turned to her Adjutant, ready to confront an issue that should have been resolved before they left the upper city. Helena’s thick robes were slowing them down, and the girl was becoming a source of embarrassment as she caught herself on every scrap of jagged metal.

She led the eighteen-year-old adjutant to a store that sold a variety of clothing, manufactured on site or bought from traders, placed a lasgun power pack in her hand and told her to go trade for something more practical. The proprietor was a mutant, a woman whose sleeveless vest exposed mineral growths on her arms, and Helena was unnerved by her childhood nightmare made manifest. Still, if there was one thing Amelia could depend on Helena for it was her healthy respect for orders.

After some time, and rather loud haggling, Helena emerged from the shop dressed in a bodyglove of brown leather. The tight-fitting garment, whilst not quite the skin-tight synthskin favoured by the Death Cults, was a far cry from her robe. Helena, who had been hidden beneath the folds of her robes for as long as Amelia had known her, seemed to glow with newfound confidence, and her golden hair hung loose behind her head. She took in a triumphal breath, only to bend over double as her lungs filled with toxic air. Soon her face was again hidden under her rebreather and those golden locks were buried under a hooded poncho, but for a moment Amelia had seen her adjutant as she would wish to be seen, rather than the false persona of the administratum adept that has been her identity for most of her life. Now equipped for their journey, Luka led the group out of the town.

They rendezvoused with the remaining stormtroopers in a hollow beneath a large section of flat metal. Past of Amelia suspected she should feel guilty about her hot shower and warm food, while these men had slept in their armour and eaten rations boiled over a block of burning hexamine. Still, she thought, the Stormtroopers would often boast in the mess of their ability to endure any hardship, so she supposed they were used to roughing it. Corporal Al’Said took them aside and briefed them on the journey ahead. They had come prepared for a long march, and each man had slung a haversack filled with rations and emergency equipment beneath the bulky power pack for their hellguns. With their hooded ponchos, their group might appear as a roving warband or group of traders, provided nobody looked close enough to see their fine leather boots or las weapons, which would be the envy of the underhive.

The miles fell behind them as they hiked away from waterfall. The paths here were as well travelled as the underhive gets, and they made a good pace along the smooth tracks of other travellers. This far from Waterfall the light began to dim, and it took some time for Amelia’s group to adjust to the near twilight. The lenses in their rebreathers would automatically compensate for the lower levels, but their disguise would be wasted if they all had glowing green eyes. On two separate occasions, their group was forced to seek shelter off the road so as to avoid meeting travellers heading the other direction. Traffic was infrequent but when people did travel along these roads, they did so in groups sometimes as much as two dozen strong. Once these caravans had passed out of sight, Amelia would bring her people back onto the road and they would continue on their journey.

In time, their route brought them away from the tracks and out into the main wastes. Here everything was a mire of twisted metal and strange organic growths. Small plants clung to whatever condensation could be drawn from the walls, little reddish weeds or pseudo-cacti bristling with spines. As the acolytes traversed the broken ground their footfalls would occasionally scatter small lizards into a dozen pockmarked burrows, they seemed to be Iberia’s answer to the common rat. Occasionally, they would spot the larger lizards that Amelia had seen in Waterfall’s flesh market, sunning themselves under the light of distant maintenance lamps, their long jaws open wide whilst small bats picked their teeth clean.

Their pace was far faster than the journey through the Wall. Though the terrain here was difficult, they had not yet met the added difficulty of verticality and their pace was much faster now that Helena no longer needed to unentangle herself from every scrap of metal. Indeed, Helena seemed to move across the ruins with a newfound grace that could not merely be explained by her change of attire, or the experience of crossing the Wall. It was as if she was finally starting to step into the light, and it warmed Amelia’s heart to see her come into her own. She still saw far too much of herself in her adjutant, and it seemed she was finally beginning to grow in confidence, just as Amelia had.

Much of the underhive is little more than mountains of rubble, but the Mechanicus had raised Hive castle about two hundred metres above the surface, and so there was a large series of open chambers in which the majority of the underhivers dwelt. Time and decay sometimes closed off chambers from each other, and hivequakes would occasionally send sections of the lower city crashing down, or erode the very ground beneath the underhivers feet. Beneath this shifting surface, Hive Castle was built atop the old city of Castle, which had grown naturally until its population became unsustainable, and the Governor petitioned the Mechanicus to sink in a hive city. Over time the skyscrapers and ha-blocks of the old city collapsed under their own weight, forming the shifting surface that now housed the underhive.

Donovan believed that the Ragged Duke had built his sanctuary in the deepest part of the Old City, where millenia of organic growth had created a geological strata that, were one to separate it from its surrounding, would show the history of Nova Iberia from its first colony to the present day, like rings on an ancient oak. To reach those crushing depths would not be easy: intact tunnels going that deep would be hard to find, and the few known entrances were fiercely guarded in the strongholds of the Undercity’s mightiest warlords. A passage to the Old City meant access to precious archeotech that could turn a clan boss into a king, or unleash ancient horrors that would destroy the clansman foolish enough to awaken them.

Over the course of his year in the Underhive, Donovan had managed to identify a small number of entrances that had been deliberately concealed, rather than fortified. He believed that the Ragged Duke used these tunnels as staging grounds for their war against the Death Cultists, which the underhivers knew only as invisible demons that descended from above to kill the strongest warriors. Since the arrival of the Inquisiton, mutant raids into the Hive had ceased entirely, likely as the Ragged Duke assessed the impact of this new player.

After a hard day’s hike through the undercity, Amelia finally reached the coordinates given to her by Donovan. The Stormtroopers spread out to secure the perimeter while Amelia reched out with her mind, searching for any consciousness that didn’t belong. She could see the eleven minds of the other Acolytes, as well as the subtly warped presence of the mutant Luka, and they stood alone for as far as her mind could reach. The entrance itself had been rendered deliberately inconspicuous beneath a metal sheet that seemed indistinguishable from the other ruins but which concealed a small tunnel made from sections of a wide pipeline with a metal ladder bolted to the wall. Past this pipe lay an arduous descent through the compressed mass of thousands of years of Imperial civilisation, at the end of which waited an army of mutants, with the Ragged Duke at their head.