The three Space Marines watched the boiling sky in the far distance with trepidation. None would ever forget the horrors they had witnessed on Ichar IV and the thought of facing such a foe again brought nothing but apprehension.

While they knew they could fight any foe and triumph, they were but a hundred warriors and, against such a numberless horde, there was only so much they could do.

The soldiers around them were numerous, though nowhere near as numerous as the tyranids. But where the defenders of Tarsis Ultra had the advantage over the alien horde was in their basic humanity, the courage that came from defending one's hearth and home.

The very thing Uriel and his sergeants lacked.

The Western Mountains writhed with motion. Thousands upon thousands of mycetic spores hammered the ground, each disgorging a mucus-covered creature that hissed and screeched in animal hunger. Swarms of beasts gathered in the shadow of the twisting, smoke-wreathed forests, the natural beauty of the ecology perverted into monstrous, alien flora that consumed the nutrients in the soil and spread a dark stain of necrotic growth across the landscape. Bubbling pools of acids and enzymes formed in sunken patches of ground, small devourer organisms plunging into the acid baths to give up the energy they had consumed to feed the voracious appetite of the alien fleet.

When enough creatures had gathered in a snapping, biting mass, the horde set off at some unseen signal, powerful hind limbs propelling the bounding swarm through the deep snow of the mountains and onto the plain below. Larger creatures stamped through the snow, their bestial jaws snapping and clawed hands sweeping aside the smaller aliens as they moved through the swarm. Tens of thousands of aliens charged down the mountains, directed to their prey by invisible cords of psychic hunger that connected them with thousands of flying gargoyles that swept ahead of the swarm and reeled them closer to their prey.

All across Tarsis Ultra, the beasts of the tyranid invasion closed on their targets.

Guardsman Pavel Leforto of the Erebus Defence Legion nervously licked his lips, then wished he hadn't as he felt the cold freeze the moisture within seconds. He desperately needed to empty his full bladder, but the latrine pits were three hundred metres behind his platoon's section of the forward trench. He cursed the need to drink so much water. At his age, his bladder wasn't the strongest in the world, and the need to drink five canteens of water every day to stave off dehydration - a very real danger in this cold climate - was a constant pain.

But the corpsmen of the Logres regiment were all humourless bastards when it came to cold weather injuries, and it was now a court martial offence to suffer from dehydration, frostbite or hypothermia.

The trench was not as cold as it had been in the weeks previous to this, though high on the periscope platform, a cold wind chilled him to the marrow despite the many-layered thermal overwhites he wore. The presence of so many soldiers raised the temperature by several degrees and the tanks had become a magnet for cold soldiers who basked in the heat radiating from their engine blocks. This section of trench alone was home to over three hundred soldiers, a mix of squads from the Logres and Krieg regiments. None of the off-world soldiers were that friendly, and treated the majority of the Defence Legion soldiers like weekend warriors, amateurs playing in the big boys' arena. This combined with fraying tempers caused by the miserable conditions, had made relations between the defenders of Tarsis Ultra strained to say the least. The initial excitement of leaving his regular post in the Erebus smelteries had long-since evaporated and he missed the predictable monotony of his work.

But more than that, he missed returning home to his wife and children at the end of the day and the cramped, yet homely hab-unit that they and three other families shared high on the north face of District Secundus. Sonya would be readying the evening meal about now and his two children, Hollia and little Solan, would be on their way back from the scholum. The ache of their absence was painful and Pavel looked forward to an end to this war when he could be reunited with them.

Banishing thoughts of home and family, he pressed his face to the rubberised eyecups of the bipod-mounted periscope magnoculars and pressed the button that flipped open the polarised lens covers. He shifted his balaclava under his helmet to get a good look through the magnoculars. The heat from his skin momentarily fogged the glass before the image resolved into clarity before him.

The bleak, unbroken whiteness of the landscape was empty as far as he could see, though he knew that the freezing temperatures reduced his depth perception and visual acuity. Still, he wasn't the only one watching this sector, so he wasn't too bothered that he couldn't see much. Seeing nothing was a good thing anyway, wasn't it?

'Anything?' asked his squad mate, Vadim Kotash, holding out a steaming tin mug filled with caffeine towards Pavel. At forty-five years old, Vadim was a year younger than Pavel and together, they were probably the oldest men in the platoon.

His friend's face was obscured by his balaclava and snow-goggles, a scarf wrapped around his mouth muffling his words.

'Nah,' said Pavel, snapping the covers back over the mag-noculars. He took the mug and, pulling the scarf from his mouth, sipped his hot drink. 'Can't see anything worth a damn in this weather.'

'Aye, I hear that. Con tells me that Kellis got taken back to the medicae yesterday. Snow blindness got him. The young fool kept taking his goggles off.'

'The provosts will haul him over the coals for that.'

'I wouldn't mind being hauled over the coals, it might warm my old bones up,' chuckled Vadim.

'It would take the furnace back in the smeltery for that now,' said Pavel.

Vadim nodded as an officer in a long, mud-stained Krieg greatcoat and a thick, furred colback studded with a lieutenant's pips stalked down the trench. He carried his lasgun slung over his shoulder and he scowled in displeasure as he marched.

'Uh-oh, it's Konarski,' hissed Vadim, tapping Pavel's shoulder, but it was already too late.

'You!' snapped Konarski. 'Why the hell aren't you watching for the enemy?'

Pavel started at the sharp bark of Konarski's voice, spilling caffeine onto his overwhites.

'Uh, sorry, sir. I was just—'

'I don't give a damn what you were doing, you are supposed to be watching for the enemy. You might single-handedly condemn us all to death with your carelessness. I'll have you on report for this, you mark my words.'

Pavel groaned in frustration as Konarski fished out a battered, and obviously well-used, disciplinary infractions notebook and a worn-down nub of a pencil.

'Right then, soldier, name, rank and serial numb—'

Konarski never got a chance to finish his question as the alert sirens blared into life all along the front line. Wailing klaxons screamed a warning to the soldiers and the trenches erupted in panicked motion as troopers fumbled for their weapons and scrambled to the trench's firing step. Pavel dropped his mug and pressed his face to the trench periscope, the altercation with Konarski forgotten.

He snapped up the covers and gasped as he saw the swarming black shapes knifing through the air towards the trenches. The entire upper half of the viewer was filled with alien creatures and he could hear the rustling roar of thousands of beating wings as they drew nearer.

Realising he no longer needed the scope, Pavel dropped to the firing step and lifted his rifle to his shoulder. Engines belched smoke as Hydra flak tanks drove forward, sending frozen mud and snow flying as their tracks churned the ground. Ammunition trucks followed the tanks, each carrying three thousand shells in easy-to-load ammo panniers, since a Hydra could pump out up to a thousand rounds a minute.