She did not exist in the darkness. She was not a prisoner hurled into the lightless depths of the world by an armoured gaoler and bound with golden chains.

She was Dalia Cythera.

And with that thought, she woke.

Information passed around Mars in a multitude of ways, along trillions of kilometres of cabling, through fibre-optics, fizzing electrical field clouds, wireless networks and hololithic conduits. The exact workings of the ancient mechanics by which many of the forges communicated were unknown, and even the magi that made use of such things did not fully understand them.

Almost all the myriad means of information transfer were, however, vulnerable to the corrupting influence of the scrapcode boiling out from the depths of Olympus Mons in the dead of the Martian night.

It moved outwards like a hunting raptor, drawn by the scent and flow of information. Everything it touched it corrupted, twisting elegantly crafted code into something vile and debased. The wondrous flickering, chattering cant of pure machine language, the gurgle of liquid data and gleaming information-rich light became a hateful birth scream of something malformed and evil.

At the speed of thought, it spread across the planet's surface, slipping like an assassin into the networks of the Martian forges and wreaking untold damage. The aegis barriers tried to hold it back, but it overwhelmed them in moments with its ferocity and diabolical invention.

A few, a very few, forgemasters were quick enough to cut themselves off from the networks when they saw the danger, but so deeply enmeshed were they with the Martian information exchange systems that it was impossible to avoid exposure completely.

Replicating itself at a terrifying rate, the scrapcode found each forge's weakest point and induced disastrous system failures at every turn.

At Sinus Sabaeus, the continent-sized assembly lines of Leman Russ battle tanks ground to a halt, and machines that had run without interruption for over a century seized up, never to operate again.

In the Tycho Brahe ammunition storage facility, a rogue set of commands raised the temperature in the promethium tanks until a catastrophic explosion ripped through the lower storage levels. Liquid flame bloomed up through the crater, igniting a devastating conflagration that engulfed the entire facility, detonating billions of tonnes of ordnance and obliterating the holdings of High Adept Jaigo.

The great Schiaparelli Repository on the Acidalia Planitia, a towering pyramid of unlocked data from the earliest days of mankind's mastery of science and gathered wisdom from across the ages, was infected with scrapcode, and twenty thousand years' worth of knowledge was rendered down into howling nonsense.

Warning klaxons and shift horns blared as the scrap-code issued commands and countermanded them an instant later, the forges of Mars screaming at the violation done to their wondrous mechanics. Machines screeched and shrieked as rogue current surged through their workings, blowing circuits and frying delicate mechanisms that would never be repaired.

Almost no corner of Mars was safe from the scrapcode, which gathered momentum and ambition as it encircled the globe in an ever-tightening web of malice.

The chemical refineries of Vastitas Borealis opened their pressure valves and flooded the workers' hive-sinks of the northern polar basin with a mix of methyl iso-cyanate, phosgene and hydrogen chloride. The deadly cloud slowly oozed down into the sinks, killing every living soul as it went, and by morning's light, over nine hundred thousand people were dead.

As if relishing this method of murder, the scrapcode then killed the astropaths of Medusa Fossae, altering the breathing mix of their life support until each psyker was being fed hydrogen cyanide gas. Within minutes, over six thousand astropaths were dead, and after one plaintive death scream that was felt in the Emperor's vaults beneath the surface of Terra, Mars fell utterly silent.

Ipluvien Maximal was one of the lucky few able to sever his links with the networks before too much damage was done, though three of his fusion reactors along the Ulysses Fossae suffered critical meltdowns, the mushroom clouds of their detonations drifting east and north, forever irradiating thousands of square kilometres of the Martian soil.

The same story was enacted all across the surface of the red planet, machines rebelling as their internal workings were overloaded with contradictory commands. The death toll climbed into the millions within minutes as forges exploded, toxic chemicals spilled through manufactories and mass-storage facilities of explosive materials cooked off in devastating daisy chains of detonations.

In years to come this night would become known as the Death of Innocence.

Only the forge of Adept Koriel Zeth escaped unscathed, the torrents of crackling scrapcode unwilling or unable to travel the glittering golden wires that had recently carried the Emperor's light along them. Like positively charged iron filings flowing around a similarly charged magnet, the scrapcode bypassed the Magma City altogether.

It was the one ray of hope in an otherwise bleak night.

Caxton and Zouche needed a shave and Severine looked as though she hadn't slept in days. Even Mellicin, logical, unflappable Mellicin, looked deflated in the aftermath of the disastrous trial of the Akashic reader. They sat around Dalia's bed in the medicae wing of the Magma City, fussing over her as medical servitors drew blood and monitored her vitals.

The room smelled of counterseptic, soap and the lapping powder Adept Zeth was fond of using on her armour.

'You gave us quite a scare, young lady,' Zouche had said as he entered the room and saw that Dalia was awake. Dalia had been touched at the genuine emotion she saw in the gruff machinist's face.

'Sorry,' she said. 'I didn't mean to.'

'Didn't mean to, she says,' said Caxton with a forced laugh, though Dalia could see the dark shadows under the young man's eyes, the puffiness where his tears had fallen. 'Yanks open a door to a chamber flooded with psychic energy and says she didn't mean to.'

'Well I didn't,' said Dalia, aware of how foolish she sounded. 'I just couldn't leave Jonas in there.'

None of them would meet her gaze and they had shared a moment of regret for the dead.

Severine had taken Jonas's death particularly hard, and Dalia reached out to take her hand. The severity she had first seen in her face had melted away over the last few weeks and Dalia's heart ached to see the sadness in her friend's eyes.

Not a single trace of Jonas had been found in the chamber, not so much as an atom of his body to prove that he had existed at all. Likewise, none of the psykers encased in the coffered dome had survived the titanic energies of the Astronomican, their desiccated corpses withered and contracted into foetal balls.

All told, the death toll was two thousand and thirty-seven, and that figure was like an adamantium chain of grief around all their necks. They did not yet know of the night of devastation that had been so recently unleashed and how slight a loss this was compared to that suffered by the rest of Mars.

Dalia had since been told that she had been languishing in the grip of an unchanging coma for over seven days, watched over by Caxton, a host of bio-monitors and a pict-camera linked to the nearby medical station.

She learned that Caxton had refused to leave her bedside, despite repeated assurances from the others that they would take shifts in watching her. It had been five hours since Dalia had woken, though the bulk of that time had been spent being questioned by Adept Zeth. Her friends had only just been granted access to her.