The buried wreck of a prospector's hauler had been almost completely obscured by the dust storms, but Equitos Bellum had scented the handiwork of its nemesis in its destruction.

No sooner had the Knight's auspex sniffed at the residue of reactor, shield and weapons, than Maven felt its gnawing desire to travel eastwards over the mountainous ridge between Tharsis and the Syria Planum in an aching pull of the Manifold.

Now they had found this corpse-filled tunnel, a charnel house of senseless slaughter, and still the Manifold pulled them onwards.

'Why hasn't anyone come to help?' wondered Maven. 'Why have they just left them?'

'Mars has bigger problems,' replied Cronus. 'You've heard the feeds. It's civil war.'

Maven heard the warring desires in his friend's voice and felt the same turmoil within his own heart. The inload feeds had been jammed with a million clamouring voices: declarations of war, pleas for aid and feral screams of hatred. The Martian forges, which had stood shoulder to shoulder through uncounted epochs of darkness and weathered those storms intact, were now doing to one another what Old Night could not.

Duty to their order told Maven they should abandon this quest and ride west with all speed to join their fellow Knights in defence of the Magma City.

But honour told him that once begun, a quest could never be abandoned, only completed.

Maven felt the angry pull of Equitos Bellum through the Manifold and knew which imperative he must obey.

'It's closer,' he said. 'I can feel it.'

'Then let's get after it,' said Cronus, riding towards the Syria Planum. 'The sooner we kill it the sooner we can rejoin our brothers.'

The Cargo-5 rolled onwards through the soaring canyons of the Noctis Labyrinthus, the darkness always seeming to draw it further and further in, as an ambush predator lures its prey. The darkness was cold and the cabin's tiny heater did little to take the edge off the chill, but after the dusty, clammy journey across the Syria Planum, no one was complaining yet.

The deeper they went, the colder it became, and white webs of hoarfrost formed on the windows, a phenomenon none of them had ever seen before. Rho-mu 31 was forced to divert valuable battery power to the heater to keep the glass clear and see where he was going.

The headlights of the Cargo-5 stuttered, barely piercing the gloom, and the atmosphere within the cabin grew stuffy and unpleasant as the air recyder failed. Hour after hour passed, and though there was nothing resembling a roadway, the base of the graben was relatively flat and the Cargo-5 devoured the kilometres.

Whenever they came to a branching canyon, Dalia would direct Rho-mu 31 with a nod of the head, as though afraid to disturb the sepulchral silence that filled the Noctis Labyrinthus.

No one questioned how she knew where she was going.

Grating static hissed from the oil-stained vox and Zouche reached down to turn it off before looking over his shoulder with a puzzled expression. 'Strange. It's not even on.'

'Mellicin did say the adepts in this region left because of technical problems,' said Caxton.

His words were said lightly, but served only to heighten their unease.

More mechanical glitches plagued them as the journey continued, though the passage of time after the first two days in the darkness was hard to judge after everyone's chronometers failed at exactly the same moment. Several hours later, the cabin's internal lights sputtered and died as they made a treacherous descent into an even deeper, shadow-thickened canyon unleavened by sunlight.

The darkness closed in on them utterly, and Dalia felt as though a cloak was being drawn around them while a host of black ghosts followed and watched from the shadows. Each of them felt a thousand eyes upon them, the hairs on the backs of their necks erect and screaming danger, though nothing threatening was visible.

Several times along the way the engine coughed and died, and each time it had to be coaxed back to life by an increasingly frustrated and nervous Caxton.

Despite the mechanical problems and the sullen, apprehensive mood that settled upon everyone in the gloom, Dalia felt a mounting sense of excitement with each kilometre that passed. They had seen no daylight and no hint of anything resembling their final objective, but with the certainty of a zealot, Dalia knew they were close.

She had no idea how deep they had penetrated into the Noctis Labyrinthus - the odometer had failed the previous day - or where they were in relation to any other living thing on Mars, but a growing ache in the back of her mind told her they were close.

The rumble of the engine cut out again, and Dalia heard Caxton groan as he prepared to venture out into the cold and the dark to get it restarted.

Rho-mu 31 shook his head. 'No need. We're not going any further, the battery's dead.'

'So what do we do now?' asked Severine, a shrill edge to her voice.

'It's all right,' said Dalia, leaning forward and wiping her hand across the cold glass of the driver's cabin. 'Look!'

Ahead of the lifeless Cargo-5, a sheer diff towered over them, its walls sparkling as though studded with nuggets of quartz. But this was no ordinary wall of rock, Dalia realised: its surface was smooth, like fused glass, and it shone with a faint internal light. Sections of the diff had fallen away over the aeons, exposing a darkened passage that deft the rock, and from which a strange mist sighed like steam from a geothermal vent.

'The breath of the Dragon,' said Dalia. 'We've arrived.'

The Himadri Precinct encircled the great, hollow mountain of the Himalazia at the crown of Terra, a mighty concourse of black, glassy marble lined with busts and statues of cowled figures. Veins of gold and red and blue threaded the marble and a thousand honour banners hung from the kilometre-high roof of shadowed arches and iron vaults.

Cold light spilled into the vast chamber through tall windows twice as large as a Warlord Titan, throwing out great spars of brightness across the tiled floor of black and white terrazzo. The light fell on the towering warrior in gold who marched along its length in the company of a smaller, white-haired man who wore the simple robes of a palace administrator.

The giant wore a magnificent suit of golden armour, wrought by the finest craftsmen and embellished with finery scrimshawed by the greatest artisans of the Imperial Fists. A mantle of red velvet edged with bronze weave hung around his shoulders and his silver hair gleamed in contrast to the lustre of his armour.

The warrior's face was craggy and tanned, browned by the light of unnumbered suns, and carved in an expression of stoic determination.

His companion was as unremarkable as the warrior was exceptional, his white hair worn long, like a mane, and his shoulders stooped with the weight of the world.

Behind this unlikely pair marched a detachment of ten Custodians in bronze armour and scarlet-plumed helms who carried long-bladed pole arms. Their presence was a formality, for Rogal Dorn, Primarch of the Imperial Fists, needed no protection.

Of all the great precincts of the Emperor's Palace, the Himadri was one of the few not to have been turned into a fortress by the golden warrior; though that fact was scant comfort to him, saw his companion, Malcador the Sigillite, Regent of Terra.

Malcador saw the wonder in Dorn's eyes as they passed beneath Shivalik Arch and the ten thousand names of its builders inlaid with gold onto the marble. Behind that wonder, he also saw sadness.

'The glory of the Emperor's fastness will rise from the ashes of this war like a phoenix,' said Malcador, guessing his friend's thoughts.

Dorn looked down at him and smiled wearily. 'Sorry. I was just calculating how long it would take to dismantle the great archway and replace it with a bastion gateway.'