How any of them didn't collide was a mystery to Dalia, though she presumed that each one would have some kind of onboard navigational system, which linked to a central network that monitored speeds, trajectories and potential collisions.

She shook her head free of the thought and forced herself to concentrate on enjoying the journey. Too often she was being distracted when she saw something new and incredible. Her thoughts would seize on this unknown factor, searching her memory for something similar before sending the creative part of her mind into a freewheeling spin as she attempted to account for the technological explanation of this new phenomenon.

They were heading for the centre of the Magma City, that much was obvious, the unmoving, unblinking servitor fused with the vehicle's control mechanisms conveying them unerringly through the heaving mass of bodies.

Their course took them onto the golden boulevard she had seen from the air, its sides lined with statues and thronged with robed acolytes. At the far end, Dalia saw a towering structure of what looked like bright silver or chrome.

As if fashioned from precisely machined blocks of silver steel, the forge was etched with geometric patterns like those of a circuit diagram, though Dalia had no idea what manner of circuit was described in its design. The servitor increased the speed of their vehicle and the enormous building soon grew in stature until Dalia's neck hurt with craning to look up at its blocky enormity.

A portion of the wall at the base of the forge slid apart and sections of the building seemed to retreat within its structure, forming a gleaming ramp that led up to a vast portico halfway up the building's side.

Dalia gripped the handrail as their vehicle began the ascent, looking behind her as the ramp disappeared as soon as they passed. The portico loomed large above them and now she truly appreciated how enormous it was, each column fashioned in the shape of an enormous piston and capped with cog-shaped capitals.

The entire building was designed as if it were a moving machine, and for all Dalia knew, perhaps it was.

At last the vehicle levelled out and the clacking of its many legs ceased as it came to a halt on the portico's wide plinth. The floor was milky white marble with dark veins running through it, and the columns towered above her. The underside of the pediment was decorated with unknown equations and diagrams picked out in glittering mosaics of gold. The sheer visual splendour was overwhelming.

A wall of bronze doors led into the mighty structure. All were open and from them poured a host of robed figures. Each wore its hood drawn forward to cover its head and each wore the number grid of Adept Zeth as a veil. Many carried strange devices in open boxes or upon their backs.

Leading the figures was a tall, slender adept with a lithe, muscular physique and a cloak of golden-red bronze that billowed behind her in the swirls of hot air.

Without introduction, Dalia knew this must be the Mistress of the Magma City: Adept Koriel Zeth.

Her body was sheathed in a flexible skin of bronze armour, her attire more like that of a warrior woman than a master of technology.

Her features were invisible, hidden behind a studded head mask and opaque goggles. Puffs of steam exhaled from a rebreather mask and a skirt of bronze mail hung low over her shapely armoured legs. Though her body armour obscured all traces of Zeth's humanity, there was no doubt as to her sex.

Every curve and every plate of armour had been designed to enhance her natural form, her slender waist, the curve of her thighs and the swell of her breasts. Fully a third of a metre taller than Dalia, Adept Zeth approached, and a delicate mist of atomised perfume came with her.

She leaned down to stare at Dalia, the glossy black orbs of her goggles like those of an insect regarding some interesting morsel that had just wandered into its lair. Zedi's head cocked to one side and a burst of static hissed from the bronze mesh to either side of her rebreather.

Moments passed before Dalia realised that the static had been directed at her, a blurted hash of machine noise intelligible to the binaric fluent.

'I can't understand you,' she said. 'I don't speak lingua-technis.'

Zeth nodded and her head twitched as though a switch had flicked inside it.

'What relationship does the ideal gas law represent?' asked Zeth, her voice rasping and the words sounding as though they had been dredged up from a little used repository of linguistic memory.

Of all the welcomes, this was one Dalia had not anticipated. She closed her eyes, casting her mind back to one of the first books she had transcribed in the Librarium, a textbook recovered from beneath a ruined tech-fortress of the Yndonesic Bloc.

'It describes the relationship between pressure and volume within a closed system,' said Dalia, the words recited by rote from memory. 'For a fixed amount of gas kept at a fixed temperature, the pressure and volume are inversely proportional.'

'Very good. I am Adept Koriel Zeth. And you are Dalia Cythera. Welcome to my forge.'

'Thank you,' said Dalia. 'It's very impressive. Did it take long to build?'

Zeth looked her up and down, the sound of electronic laughter crackling from her voice unit. She nodded. 'It did indeed. Many centuries of work were needed to build this forge, but even now it is not complete.'

'It isn't? It looks complete.'

'From without, perhaps, but within there is much yet to be achieved,' said Zeth, her delivery growing more fluent as she spoke. 'And that is where you come in.'

'How do you even know me?'

'I know a great deal about you,' said Adept Zeth, looking at the space above Dalia's head. 'You are the only daughter of Tethis and Moraia Cythera, both deceased. You were born in medicae block IF-55 of the Ural Collective seventeen years, three months, four days, six hours and fifteen minutes ago. You were trained to read and write at age three, indentured to the Imperial Scriptorium aged six, and trained in the art of transcription aged nine. You were apprenticed to Magos Ludd aged twelve and assigned to the Hall of Transcription aged fifteen. You have six commendations for accuracy, twelve citations for inciting behaviour deemed to be incompatible with working practices and one instance of imprisonment for violating the Laws of Divine Complexity.'

Dalia looked up, half-expecting to see illuminated letters displaying her life story for Adept Zeth. She saw nothing, but it was clear from the tone of Zeth's voice that she was reading these facts from somewhere.

'How do you know all that?' she asked.

Zeth reached down and brushed a metallic fingertip across Dalia's cheek, and she felt a warm glow as the electoo implanted beneath her skin upon her induction to the Hall of Transcription came to life. She reached up and placed a hand on her skin.

'You can read my electoo?'

'Yes, but I can discern much more than simple biographical knowledge,' replied Zeth. 'All data can be read, presented and transferred with a glance. Though invisible to you, I see a liminal skein of data filling the air around you, each ghost of light a fact of your life. I can see everything about you, all the things that make you a person in the eyes of the Imperium.'

'I've never heard of anything like that.'

'I am not surprised,' said Zeth with a trace of pride. 'It is a function of data retrieval and transfer that I have only recently developed, though I have great hopes for its eventual employment throughout the Imperium. But I did not bring you to my forge only to impress you with my technological developments, I brought you here because I believe your understanding of machines and technology runs parallel to mine.'

'What do you mean?'

'The Martian Priesthood is an ancient organisation and is learned in the ways of technology, but our grasp of such things is limited by blind adherence to dogma, tradition and repetition. I believe that our future lies in the understanding of technology, that only by experimentation, invention and research will our progress be assured. This view is not widely held on Mars.'