Then they heard the scratching of alien claws at the door to the control room.

Tyren Mallick shut out the pain of his torn shoulder and painfully reloaded his rifle, the trembling of his fingers making it that much more difficult. A blood-soaked bandage wrapped his shoulder and chest where fragments of an exploding spore had ripped into his flesh. Merria had pulled out the sizzling pieces of bony shrapnel from his shoulder, but the wound had refused to heal, weeping a constant gruel of infected blood.

'Why's the sky gone a funny colour, dad?' asked Kyle, his voice trembling in fear as he looked through the molten remains of the sheet metal over the windows. The normally slate grey sky boiled a loathsome, bruised purple and unnatural lightning speared through the violet sky, lighting the mountains in a lurid, unfamiliar light. A rain of dark objects fell to the plains below, amid the burning rain that ate away at the metal roofs of Hadley's Hope and had forced its people to abandon the barricades and take refuge in the schoolhouse, the only structure large enough to contain everyone.

The men of Hadley's Hope carried a mix of weapons, from ancient rifles that would be lucky not to misfire and take their wielder's hand off, to freshly oiled lasguns earned in service of the local defence forces. Twenty-three crying children huddled in the centre of the schoolhouse, their mothers and teachers doing their best to calm them with songs and prayers.

'I don't know why, son,' admitted Tyren, finally pushing the bullets home in his rifle. He rose from the table and joined his son at the window. Alien spores like grotesquely swollen and veined balloons had been falling from the sky since daybreak, and though most of them had been carried into the high peaks of the mountains by updrafts from the plains below, more were drifting back down as night fell and the air cooled.

At first, the people of Hadley's Hope had watched them with fearful curiosity, until a pulsating spore with a frill of trumpet-like cones and trailing fronds had drifted into the settlement. Pastor Upden had confidently walked up to the mysterious object and shot it at point blank range, expecting it to simply deflate. Tyren had watched in horror as the vile globule exploded, showering the pastor with a thick, viscous fluid and his screams echoed from the farthest corners of the settlement. Tyren had run to help Upden, but it was too late, his skin was already blistering and sloughing from his bones as the alien acids ate his flesh away. He screamed piteously until his throat melted and his lifeless body dissolved into a stinking slime.

Since then they had taken great care to shoot down any spores before they reached the settlement.

'You stay alert, Kyle, and holler if you see anything.' Tyren said, staring through the dripping, corroded holes in the metal. The lights from the townships below were gone, and he had been unable to reach anyone in Pelotas Ridge for several hours now.

The lights here were failing too, as the acid rain burned through the cables that didn't ran underground, and Tyren knew that soon the entire community would be in darkness. He tried to ignore the sobbing of the children and the trembling voices of the women as he saw movement on the road below. The ground undulated as though it was alive and the rain glistened from the carapaces of thousands of… things as they ran towards the small settlement.

He knelt and fished a battered but serviceable pair of magnoculars from his pack and trained them on the road. The unnatural darkness made it hard to see much of anything, but his breath caught in his throat as he saw a sea of creatures, all fangs and talons, swarming uphill.

'Emperor save us,' he whispered, dropping the magnoculars. 'Everyone with a gun get to someplace they can shoot from,' he shouted.

He grabbed a pale-faced man next to him and said, 'Radek, take ten men upstairs and shoot from the balcony, the canopy will give you shelter from the rain.'

Radek nodded and ran off to obey Tyren's command.

Tyren looked over to his wife and daughters, giving them a wave of reassurance before finding a loophole in the wall to fire his rifle from.

Kyle shouldered his rifle and stood beside his father, a nervous smile creasing his face.

'I'm proud of you, son,' said Tyren and Kyle nodded.

Tyren peered into the gloom, seeing the rippling swarm of creatures leaping and bounding across the barricades at the end of the road.

'Here they come!' he yelled. 'Open fire!'

Children screamed as the schoolhouse was suddenly filled with noise. Gunsmoke fogged the air and the crack of weapon fire in such a confined space was deafening. Tyren saw several creatures fall, hearing more shots from upstairs.

Over the crack of gunfire, he heard a whistling scream, similar to that of incoming artillery fire, and flinched as something heavy smashed into the roof of the building. He heard timber splinter and screams from upstairs, but knew he could do nothing to help the men stationed there. The ground trembled as more objects fell from the sky and struck with incredible force.

He shot again and again into the mass of beasts, their swollen skulls and armoured carapaces deflecting all but the most accurate shots. They swarmed into the town, spreading out and closing on the schoolhouse.

A thunderous impart outside threw Tyren to the floor and blew out the windows facing the street. A section of wall collapsed and the sheet metal was blasted from the walls. Hot, reeking air blew in.

Through the hole, Tyren could see that the generator building was on fire, and there was a huge object, like a lumpen boulder, rocking in the wide crater its impact had caused.

Smaller creatures leapt towards the hole in the wall and Tyren rolled to his feet, firing wildly into the breach. Flames from across the street silhouetted the creatures and, together with another three men, they were able to kill all the monsters attempting to force their way inside. The roof of the generator building collapsed, sending sparks soaring into the darkness, a shriek of something in pain echoing from beneath the rabble.

'Get something to block this!' he yelled, firing into the mass of creatures until his rifle was empty. He fumbled for another clip as three women dragged over a heavy table and some desks, overturning them before the gap in the wall.

Gunfire and the sound of screaming children filled Tyren's senses as he reloaded his rifle. He heard impacts on the few remaining windows covered by the sheet metal and saw another give way as a horrific alien creature forced its way inside.

It leapt into the room, rain steaming from its glossy, armoured carapace. Hunched over and six-limbed, its bestial face hissed in alien hunger.

Tyren shot at it, but missed, blasting a chunk of plaster from the wall beside it. The beast ignored him, pouncing on the defenders at the northern wall. He screamed as he saw Kyle turn to face the monster and raise his rifle. But the creature was inhumanly fast and its scything claws slashed out, disembowelling his son before he could fire.

'No! No! No!' Tyren screamed, firing again. His bullet caught the creature at the base of its neck and exploded its head in a spray of dark ichor. He dropped his rifle and ran towards his son, but it was too late, his boy was already dead.

He cried out in anguish, cradling his son's body. Through a mist of tears he saw the ruins of the generator building heave upwards, as something vast hauled itself from the wreckage.

He fumbled for his rifle, as more cries filled the school-house. A huge shape lumbered across the street and slammed into the side of the schoolhouse, smashing down the wall and tearing a portion of the ceiling with it. The thing's body was on fire and it shrieked in fury and pain as it battered its way inside.