Cavalerio nodded, sweat streaming from his brow, and his mouth dry. His heart was beating in brutal syncopation with the fiery heart of Victorix Magna, the straining power of a supernova at the engine's core burning hotter and faster than it was ever designed to. He could hear Magos Argyre's desperate supplications to the reactor's spirit and felt the anguish of the mighty engine in the numbness spreading through his limbs.

The image of the Imperator filled his senses, both through the viewscreen and through the Manifold. Data scrolled like liquid light through his mind, and he drank in the colossal feats of engineering that had gone into its construction and the utter lethality of its existence.

Its limbs were death incarnate, the grinning skull-face an abominable harbinger of destruction. The bristling weapon towers and bastions were a martial city-fortress carried on the back of an ancient G.o.d, though this burden was borne willingly and not as a punishment.

To fight such a thing would be the greatest achievement of any princeps, but it would probably also be his last.

The monster took another step, taking with it any chance that this crossing of the Tempest Line was accidental.

*Princeps Sharaq requests instructions,' called out Kuyper. *Arcadia Fortis requests permission to fire.'

*Vulpus Rex and Astrus Lux moving into flank fire positions,' noted Palus.

*Tell them to hold positions, d.a.m.n them!' shouted Cavalerio, his pulse racing like the roaring discharge of a gatling cannon. *No one opens fire unless I give the order. Make sure that last part is especially clear, Kuyper.'

*Yes, my princeps.'

Cavalerio had the sensation of events sliding beyond his control, and he fought for breath as the fire from his loyal engine's heart poured through the virtual marrow of his body like blood from a ruptured artery.

His vision blurred, the edges of the Manifold swimming like a badly-tuned picter.

Victorix Magna was hurting, hurting badly, and Cavalerio knew he had to end this ugly confrontation soon.

But how to do that without beginning a firefight that would destroy them all...

RAPTORIA STRAINED AT the edges of Princeps Kasim's control, a feral, b.e.s.t.i.a.l thing that demanded blood and poured violent thoughts into his consciousness. Its murderous heart had tasted the enemy's presence and felt the heat of its metal skin. It wanted to kill.

Kasim looked down at the gold cog medallion he wore and focused his mind on the discipline encoded into his thoughts by the Legio Magi before beginning this walk. Clogged data from previous engagements were washed from the peripherals grafted to the frontal lobes of each crewman's brain to ensure each engagement was begun without the mental baggage of the last, but the hungry taste of battle was impossible to wash away completely.

No engine ever really forgot the hot, metallic flavour of war.

Kasim could feel his steersman's efforts to keep the aggression from Raptoria's movements and could hear the engine's hunger for battle in the thudding, roaring drumbeat of her reactor.

Raptoria wanted to fight and, d.a.m.n it, so did he.

Princeps Cavalerio was holding his fire and so too must they, but it was galling to see the engines of Mortis so brazenly insulting the honour of Tempestus. To allow this art of defiance to go unpunished was a bitter pill to swallow, and he could already feel Raptoria's ire building within his skull with the malicious promise of future pain to come.

*Power up weapons,' he ordered in an effort to a.s.suage the engine's bloodl.u.s.t. *Disengage safeties and surrender all firing authorities to me.'

By a.s.suming all firing authorities, he was making sure that the feral heart of Raptoria didn't overwhelm the low-grade brain coding of the emplaced gun-servitors and open fire herself.

Kasim didn't want his engine to act without his control, but if a shooting war started, he was going to be ready to prosecute it to the best of his ability.

*Why isn't the Stormlord opening fire?' wondered Moderati Vorich.

*Are you in a hurry to die?' asked Kasim. *Because that's what will happen if we let this get out of hand.'

Despite his rebuke, Kasim was wondering the same thing. Mortis had clearly breached the Tempest Line, and Cavalerio was quite within his rights to fire. As much as his heart was spoiling for a fight, Kasim knew that the odds against victory were high.

Staring into the Manifold, Kasim saw the heroic form of the Victorix Magna standing firm before the monstrous, towering might of the Imperator. Beside her stood Arcadia Fortis and Metallus Cebrenia, all three engines dwarfed by the enemy engine.

*What are you planning, Stormlord?' whispered Kasim.

The Imperator loomed on the Manifold, a glowering G.o.d of war that could destroy them all. A few more steps and it would be right on top of them.

IN THE CABIN c.o.c.kpit of Metallus Cebrenia, Princeps Sharaq was wondering the same thing as Kasim. Moderati Bannan counted the ever-increasing distance Aquila Ignis was striding into the territory of Legio Tempestus.

Increasing the angle of his view through the Manifold, Sharaq saw Victorix Magna standing proud beside him, venting hot exhaust gases and sweating lubricant from its overflows. Even without the spiking data readings, he could tell that the venerable engine was suffering.

*Come on, Indias,' he whispered. *Hold her together a little longer.'

He transferred his view outwards, seeing the agile, snapping forms of Vulpus Rex, Astrus Lux and Raptoria darting around the edges and rear of the approaching Imperator like pack wolves hunting a stag. Ever bellicose, their weapons were powered and ready to fire.

The ground shook and Sharaq could feel the tremor through every joint of his engine's structure. Inertial dampers could compensate for most fluctuations in a t.i.tan's surrounding environment, but the mighty tread of such a colossal enemy was beyond its power to completely dissipate.

He looked down at the far away ground, feeling a stab of pity for the ma.s.sed ranks of skitarii gathered around his engine's splayed feet. To face a beast like the Imperator from a Warlord's c.o.c.kpit was a terrifying enough prospect, but to stand naked before it without the protection of voids and armour...

That was courage indeed.

*Range to target?' asked Sharaq, fighting to keep his tone even.

The question was unnecessary. He could already see that the Imperator was less than three hundred metres away through the Manifold, point-blank range by any normal measure of things, but insanely close in this situation. He could already hear the squeal and rasp of the voids as their fields warbled with the proximity.

*Two hundred and fifty metres, my princeps,' said Bannan.

He spared a glance to his left.

Victorix Magna stood, implacable and immovable, before the marching Imperator, and Sharaq loved the Stormlord for his resolve as much as he was frustrated by his inaction. The tension within the c.o.c.kpit compartment of Metallus Cebrenia was unbearable.

Then a harsh, deafening squall shrilled across the vox frequencies, a filthy blurt of continuous, corrupted code noise that sounded like throaty laughter. Sharaq flinched and his sensori screamed as the wailing shriek tore at their hearing.

*What in the name of the Omnissiah is that?' yelled Bannan, s.n.a.t.c.hing the vox-set from his head.

Sharaq killed the audio as the cackling laughter code burbled over the vox and the booming warhorns of the Mortis engines echoed from the towering cliffs of Ascraeus Mons.

The Imperator lowered its weapon arms, every horn, bell and augmitter upon its colossal spires and bastions blaring in disdain. The noise was unimaginably loud, broadcast across every audible wavefront and code frequency.

Debased and dirty codelines conveyed vile algorithms that Sharaq felt worming their way into his peripherals like viral code, and his aegis protocols fought to prevent them from reaching the deep sub-systems of Metallus Cebrenia.

*Princeps!' shouted Bannan. *Enemy course change detected.'

Sharaq gasped, his mind awhirl as his implants defended his neural paths from infection by the sc.r.a.ppy code fragments carried on the war-scream of the Imperator. He forced his mind through the clotted data packets of black, oozing information that blurred his vision and saw that Bannan was right.

The Imperator was changing course, its stride swinging to the east.

Like a great ocean liner travelling at speed, the course of such a vast machine did not change swiftly and its new heading would barely carry it past the south-eastern skirts of Ascraeus Mons.

*Dolun? Intercept plot,' hissed Sharaq, the beginnings of a blistering headache building behind his eyes. *Where's it going?'

His sensori didn't answer, and Sharaq twisted his head to see Dolun lying supine on his reclined couch. The man's eyes rolled back into his skull and foaming spittle gathered at the corners of his mouth.

Sharaq meshed his senses briefly with Dolun's station, feeling the hash of viral code replicating like a plague within his I/O ports, ready to spill out into the guts of the war engine.

With a thought, Sharaq cut the link between Dolun's interfaces and the rest of the t.i.tan, but even as he did so, he could feel the sc.r.a.pcode trying to find another way in.

*Moderati Bannan!' shouted Sharaq. *Disengage Sensori Dolun from his station. Now!'

Bannan looked over at Dolun, who was convulsing as his corrupted cybernetic enhancements began fitting with the power of a grand mal seizure. Bannan disengaged his hard plugs as quickly as he dared and lurched across the sensori station, unsteady on his feet after so brutal a separation from the MIU.

Sharaq turned his attention from the compromised sensori officer and followed his own track on the enemy engines. An overlaid map of the Tharsis Montes swam into view, grainy and washed with fragments of faulty code. A red line extended from their current position, swinging around to the north-east and extending towards the port facilities of Tharsis Tholus, the primary embarkation point of Astartes supplies from the fabricator loc.u.m's Mondus Occulum forge.

Sharaq dismissed the map as the shriek of voids filled the c.o.c.kpit with a warbling, squealing howl of feedback. Like a million nails down a blackboard, t.i.tanic energies pushed against one another, sc.r.a.ping their invisible power together and sending flaring, whooping coils of colourful lightning discharge into the air.

*Sensori disconnected,' called Bannan, and Sharaq looked round to see Dolun jerking and twitching on the deck, lubricant and jellied brain matter leaking from his cranial plugs.

*Good work, Bannan,' said Sharaq. *Leave him and get back on station.'

Sharaq returned his attention to the Manifold, watching in ashamed relief as the might of the Imperator swung yet further away and the spine-shearing sound of void interference abated.

*All Tempestus engines,' he said, forcing a channel through the howling static that still laced the airwaves. *Ease weapons, I repeat, ease weapons. Mortis are turning away! Acknowledge!'

One by one, the affirmations of the Tempestus engines appeared on the Manifold, and Sharaq let out a shuddering breath as he realised how close they had come to igniting a shooting war on the surface of Mars.

The Imperator's escort of Warlords moved with it and the war machines of Legio Mortis began tramping away, each step carrying them further from the domain of Tempestus.

Mortis was leaving, but Sharaq wanted to be sure they weren't about to turn back for another provocative pa.s.s.

*Raptoria, Vulpus Rex, follow Mortis and make sure they keep on their way,' he ordered, wondering why the Stormlord was not issuing the order himself. *Keep a safe distance back, but make sure they go.'

The two Warhounds set off without bothering to acknowledge his order, and Sharaq slumped deeper into the moulded leather of his reclined seat. Sweat coated his brow and his hair was soaked. He closed his eyes for a second, shutting out the data noise of the Manifold and letting the human part of his mind process the near calamitous events of the past few minutes.

Had it really been so short an engagement?

He opened his eyes as the nagging static of the vox remained unbroken by orders, information requests or any form of leadership from Victorix Magna.

Sharaq looked over to the Stormlord's engine, a terrible sense of dread building in his gut as he saw that Victorix Magna remained as she had since taking up station before the Imperator. That dread built as he saw fluid drooling in a black rain from her torso and that the hissing plumes of superheated steam that ought to gust like breath from exhaust vents beneath her shoulder carapace had ceased.

The engine's head was bowed, her limbs slack against her sides.

*Victorix Magna,' called Sharaq over the Manifold, his fear rendering his communication sharper than he intended. *Princeps Cavalerio, please acknowledge.'

There was no response.

*Stormlord, please respond immediately!'

A shift of view in the Manifold and Sharaq's head sank to his chest as he inloaded the auspex readings of the Stormlord's mighty engine Victorix Magna was dead.

THOUSANDS OF KILOMETRES to the south of the confrontation between Mortis and Tempestus, deep in the desolate, empty wilderness of the southern pallidus, wind-borne ash blew across the cratered wastelands at the edge of the Daedalia Planum.

Even further south, the horizon burned with colourful fire, the skies striated with chemical pollutants and reeking gases expelled from the ma.s.sive refineries that encircled the planet's equator.

Only the hardiest scavengers attempted to eke out a living in this region of Mars, the spoil pickings usually too thin and too laden with toxins to be of any real use. One such scavenger was a man named Quinux, a wizened prospector and former Skitarii whose body had rejected the gross implants necessary for full a.s.similation into the ranks of the Mechanic.u.m's soldiery.

Quinux scoured the deserts and hardpan of the Daedalia Planum in a ramshackle Cargo-5 bulk-hauler that pulled a tender filled with sc.r.a.p metal, held together by faith, hope and fervent devotions to the Machine-G.o.d. Its plates were caked with rust and its tracks streaked with corrosion from prolonged exposure to the hostile environment.

Acrid fumes belched from the exhausts of his crawler, and the interior of his pressurised cabin smelled of sweat, recycled nutrient paste and excitement. A cracked and filmy auspex panel hung from the roof of the cabin, pinging with a hard return of solid material.

Quinux hadn't seen a signal this strong in decades and knew that this find could be the making of him. Whatever it was, it was big, and his head darted from side to side, peering through the crazed gla.s.s of his cabin as he searched for any other scavengers that might have picked up this juicy find, not that he could see much through the whipping scads of dust and ash that swirled around the crawler.

His vehicle dipped into a gentle slope that gradually widened out into a shallow crater. The ground under the tracks was soft, irradiated sand, carried there by the freak atmospherics that blew from the monstrous refineries of black iron in the south.

The pings of the auspex grew more urgent, and he saw that he was practically right on top of his find, though he couldn't make out much beyond the dirty gla.s.s. Unhooking the auspex from the roof, Quinux hefted a simple bolt-action lascarbine from the back of his cab and checked the load.

There wasn't much left in it, but enough to deal with any feral servitors that might be lurking out in the wasteland. Looking at his useless augmetics, Quinux felt a certain sympathy with the poor, wretched servitors, but not so much that he wouldn't put a bolt through their skulls if they tried to get between him and his find.

Next he lifted his pack and slid his arms through the straps before wrapping his rebreather hood tightly around his head. Quinux then opened the cab to the elements, wincing at the force of the gale that plucked at his robes and threatened to slam the door back in his face.

Getting too old for this life, he thought as he climbed down the ladder and stepped onto the sand. He followed the strident chimes of the auspex towards a large dune field ahead of him, trying to make out what it was reading. He couldn't see anything valuable, but as he drew closer, he saw that the nearest dune was a d.a.m.n sight taller and more regular in shape than the others.

Consulting the auspex, Quinux was pretty sure that whatever he was picking up was beneath the dune. Perhaps a flyer had crashed or an ore tanker had been forced to ditch and then been covered by the sands before its crew could send out a distress signal.

Whichever it was, it marked the end of a lean patch for Quinux Fortran.

He slid the auspex into a zipped pocket in his robes and slung his rifle as he approached the dune, clambering up on all fours as the sand spilled away beneath him. Climbing the dune was hard work and he sweated profusely in the dry heat.

Quinux reached the top of the dune and began clearing away the sand with a collapsible shovel from his pack. With quick, economical strokes he dug down into the sand, widening and deepening the hole as he went.

Pausing only to take regular sips of brackish water from his hide canteen, Quinux gradually cleared the top of the dune. The wind attempted to thwart his labours, blowing fresh sand and ash back into the hole, but after an hour of digging, his shovel struck metal and he gave a grunt of pleasure.

*Right, let's see what you are then,' he said, dropping the shovel and sweeping his gloved hands over the find.

It was metal sure enough, fresh and untainted by corrosion or rust. The surface patina was blackened, as though it had been scorched by intense heat, but as he sc.r.a.ped the edge of his shovel across it, he could see that the damage was only superficial.

He cleared more sand away, guessing that the main body of whatever lay beneath him was roughly spherical from the curve of the exposed metal. More shovelfuls were scooped from the ground, and Quinux frowned as he saw the outline of what looked like some kind of battle robot emerge.

Three blisters of metal faced him, like sensor domes, but devoid of life.

*Now what in the name of the Omnissiah would you be doin' out here?'

The auspex chimed. Loud. A strong signal.

Puzzled, Quinux dug the device from his robes and looked around him for the source.

He could hear the roar of engines above the howl of the wind, but couldn't pinpoint its source. Quickly he swept up his rifle, ready to defend his find, but there was nothing to see.

A harsh beam of light stabbed from the sky above him and Quinux shielded his eyes as the roaring engine noise leapt in volume. The down-draught of a flyer's powerful jets blew up a storm of smoke and dust.

He couldn't see anything through the whipping ash, but kept his rifle pulled hard into his shoulder. The pitch of the engines changed from a howl to a whine as the craft descended, and moments later the stablight was replaced with the diffuse glow of landing lights.