The fires of the explosion expanded rapidly, quickly eclipsing the doomed Argus and smashing into the other vessels of the Imperial fleet. Six defence monitors and as many system ships vaporised as their magazines and fuel stores exploded. The Cobras of Cypria squadron broke apart as their store of torpedoes cooked off in the launch bays, though the ill-fated Cobra of Hydra squadron miraculously survived.

The launch bays of the Kharloss Vincennes blazed as fuel stores caught light, the blast doors melting shut and rendering them unable to recover previously launched squadrons of fighters and bombers. Well-practiced fire drills saved the ship and her captain's quick manoeuvring put her prow-first into the detonation and lessened the buffeting Shockwave's effect.

The Sword of Retribution, the Yermetov and the Luxor, shielded from much of the blast's force, were spared the worst of the damage, though their corridors echoed to the sound of hull breach klaxons and yelling damage control gangs.

Blood-red light bathed the control bridge of the Vae Victus, the sacristy bell ringing as though the ship herself was screaming. Sparks and jets of hydraulic fluid spurted from shattered control panels, but Tiberius knew they were lucky still to be in one piece.

The Vae Victus had been stern on to the explosion and its force had hurled her about like a leaf in a hurricane, but Admiral Tiberius's quick thinking had put her clear of the main destructive energies of the hell that had engulfed the majority of the Imperial fleet.

'Damage report!' bellowed Tiberius.

'We've got hull breaches on decks six, seven and nine,' reported Philotas. 'The engines are operating at fifty per cent efficiency and we've lost most of the turrets on our rear quarters.'

'What of the rest of the fleet?' asked Tiberius, dreading the answer.

'I don't know sir. The surveyors are having trouble penetrating the electromagnetic radiation released by the blast.'

'Get me Admiral de Corte, we need to get control of this situation, now.'

'Aye, sir.'

Tiberius lurched across the buckled deck to stand beside the plotting table, trying to make sense of the confused hash of imagery displayed there. A red haze filled the bottom of the schematic, the slate unable to display enough symbols to represent the tyranid fleet. Scattered blue icons faded in and out of focus as the surveyors fought to lock down the positions of the Imperial vessels.

'Emperor save us,' whispered Tiberius as names of vessels began flickering up next to the blue icons. Precious few, he saw. He frowned, scanning the table for the icon representing the Argus. Tiberius looked up as Philotas said, 'The Argus is gone, sir.'

'Gone—' echoed Tiberius.

'She caught the full force of the blast. There's nothing left of her.'

The lord admiral fought down his shock at the destruction of so mighty a vessel as the Argus and the death of her crew.

'And the rest of the fleet?' he asked, quietly.

'It looks like the local ships took the worst of the blast, but we've lost the Cobras and the Argus. The Sword of Retribution is damaged, but under power, and the Kharloss Vincennes is still with us though her launch bays are out of action.'

Tiberius nodded curtly, assessing the scale of the catastrophe and knew that the campaign in space was over.

'Issue a general communication to all vessels. I am taking command of the fleet. Order all ships to disengage. Get clear of Tarsis Ultra and rendezvous at Calydon.'

'Admiral?'

'Do it!' snapped Tiberius. 'Fighting an unwinnable battle is of no value if by doing so we lose the war. Now do as I say.'

Philotas nodded and dispatched the admiral's orders as Tiberius gripped the edge of the plotting table. Nothing now could be gained by fighting the advancing tyranids in space and he would not be responsible for dooming every man of the Imperial fleet.

Whatever came next, the defenders on Tarsis Ultra would have to face it on their own.

NINE

A cold wind blew across the tops of the Cullin Mountains, howling across the rocky ground below and stripping any lingering warmth from the bright morning. The air was crisp, but the sun was bright and low, preventing the foaming waters of the mountain springs from freezing over. Splashes of emerald green forests dotted the lower slopes of the mountains and, here and there, herds of shaggy yrenbacks made their way back down slope to the warmer plains from their drinking grounds.

Suddenly, the motion of the herds halted, each animal raising its long, furry neck into the air, as though scenting a predator. The herds milled in confusion, drawing closer to one another, agitated at their inability to identify the threat they all felt. The animals brayed in confusion, ears flat against their skulls.

A scattershot darkness covered the flanks of the mountain as a host of shapes flashed across the sky. All across the mountains, puffs of snow and rock were thrown skyward by the tremendous impacts of falling objects. The herds scattered as more and more objects dropped from the sky, churning the surface of the mountains with their numbers.

The clouds above flashed with purple lightning as spores burst within them, dispersing a multitude of contaminants and viruses that instantly began working to alter the climatological balance of the planet's atmosphere. Heat built up rapidly, increasing the air pressure and causing actinic bolts of lightning to arc from cloud to cloud, dispersing them as a viscous, toxic rain.

In minutes, the newly risen sun was obscured by the sheer mass of spores falling from the heavens. Terrified yrenbacks ran backwards and forwards across the mountain sides, leaping through the deep snow in their blind panic. Churning motion erupted from the steaming spores that had landed in their midst, flashing claws and alien screeches as the creatures within them emerged and sought something to kill. Driven into a frenzied killing fury by the hive mind and bio-engineered, super-adrenal chemicals, the first wave of tyranid invaders hacked entire herds of the grazing animals to bloody ruin before collapsing and dying, spent by the fury of their assault and their inability to survive the freezing temperatures.

Thousands of tyranid organisms in the first wave perished as the numbing cold of Tarsis Ultra froze them within minutes of their arrival. After burning virtually all their bodily energies in their initial surge of violence, and without reserves of fat, none could survive more than a few minutes before perishing.

But none of this mattered, for as each creature died and the hive mind became aware of the local conditions on the prey planet, it simply adjusted the biological physiology of its warrior organisms, enabling them to produce more insulating tissue and energy reserves that would allow them to survive for longer periods.

Amid the loamy earth of the lower forests, the thick, biological rain soaked into the tree canopy and saturated the earth with its bacteria-laden substance. Microbes containing the genetic blueprint of tyranid fauna spread rapidly through the ground, assessing and digesting the chemical content of the soil before turning that energy into horrifyingly fast growth spurts.

Multicoloured fronds ripped their way through the silver bark of the trees and twisting vines and creepers surged from the moistened ground. Again, the cold of Tarsis Ultra dramatically shortened the plants' lifespan, but as each leaf and creeper died, it vomited a host of fresh spores into the atmosphere and the cycle began again.

As each generation of plant went through its brief life cycle, the chemical reactions fermenting in the ground began raising the temperature of the surrounding air. Streamers of heated air drifted from the ground, warming the burgeoning plant life until the rate of growth was rising exponentially. Jagged spore chimneys of thick, vegetable matter broke through the hot earth and pushed skyward, their root structure burrowing through the permafrost to the nutrient-rich soil below. Hot steam and exhaust gasses from the biological conflagration below belched from the chimneys, sending yet more spores high into the atmosphere to be spread by the prevailing winds. As the atmosphere heated even more, strong updrafts of warm air rose, meeting the cold air descending from the mountaintops to create freak weather patterns that spread the contamination of the tyranid organisms even further.