Joachim felt his friend's glare and said, 'You almost had us in the irrigation ditch.'

'Maybe,' admitted Corin. 'But I didn't, did I?'

'Only because I took over.'

Corin shrugged, unwilling to concede the point, and allowed Joachim to continue driving the harvester in relative peace. He removed his thin gloves and flexed his fingers, attempting to work out the stiffness in his joints. Holding onto the juddering control columns of a harvester and trying to guide it around the huge fields was punishing work.

'These gloves are useless,' he complained. 'They don't help at all.'

Joachim grinned and said, 'So you haven't padded them out yet?'

'No,' replied Corin. 'I was hoping your Elleiza would do it for me.'

'I wouldn't hold your breath, she already runs after you like she was your wife.'

'Aye!' chucked Corin, 'She's a good lass. She looks after me well, so she does.'

'Too well,' pointed out Joachim. 'It's time you got your own woman to look after you. What about Bronagh, the medicae in Espandor? I heard that she was sweet on you.'

'Bronagh. Ah, yes, she's a girl of rare taste,' laughed Corin.

Joachim arched an eyebrow and was on the point of replying when the world exploded around them. A thunderous impact struck the side of the harvester and both men were hurled against the cab's interior as the giant vehicle lurched sideways. Joachim felt blood on his scalp and reached for the controls as the harvester began to tip.

He pulled back on the column, but it was too late, the left track slid from the road into the ditch and the entire vehicle rolled over.

'Hold on!' yelled Joachim as the harvester toppled onto its side with a crash of twisted metal. Broken glass showered them and Joachim felt a jagged edge slice open his temple. The harvester slammed down into the field, hurling giant clouds of corn and dust into the air as it toppled onto the dry earth. Its enormous tracks ground onwards, churning air as the engine continued to turn over.

Almost a minute passed before the side door of the cab swung open and a pair of booted feet emerged. Gingerly, Joachim lowered himself out of the cab and splashed down into the knee-high water of the irrigation ditch that ran between the road and the field. He landed awkwardly and cursed, clutching his braised and gashed head. Corin groggily followed him into the ditch, cradling his arm close to his chest.

Wordlessly, the two men surveyed the damage done to the harvester.

The hopper was a twisted mass of buckled metal, smoking fragments and the stinking residue of burned corn all that remained of its centre section, where it appeared that something immensely powerful had struck.

'Guilliman's oath, what happened?' asked Corin, breathlessly. 'Did someone shoot at us?'

'I don't think so,' replied Joachim, pointing to a pillar of white smoke billowing skyward some hundred metres further into the field. 'But whatever it was, I bet it's got something to do with that.'

Corin followed Joachim's pointing hand and said, 'What the hell is it?'

'I don't know, but if it's a fire, we've got to get it out before the whole crop goes up.'

Corin nodded and clambered painfully back into the harvester's cab, unclipping a pair of fire extinguishers from its rear wall and dropping them down to Joachim. With some difficulty they climbed the sloping rockcrete wall of the ditch, Joachim turning to pull Corin up as he reached the top.

Hurriedly, they made their way through the field, their passage made easier by virtue of the long, dark scar gouged in the earth that led towards the column of smoke.

'By Macragge, I've never seen anything like this,' wheezed Corin. 'Is it a meteor?'

Joachim nodded, then wished he hadn't as hot stabs of pain thundered in his head. 'I think so.'

They reached the lip of the crater and pulled up in astonishment at what lay within.

If it was a meteor, then it didn't look anything like either man imagined it might. Roughly spherical and composed of a leprous brown material, it resembled a giant gemstone rippling in a heat haze. Its surface was smooth and glassy looking, presumably from its journey through the atmosphere. Now that they could see it clearly, the two men saw that it wasn't smoke that billowed from the object in stinking waves, but steam. Geysers of the foul smelling vapour vented from cracks in its surface like leaks in a compressor pipe. Even from the edge of the crater they could feel the intense heat radiating from the object.

'Well it's not on fire, but it's still damned hot,' said Joachim. 'We need to cool it down or it could still set light to the crop.'

Corin shook his head and made the sign of the aquila over his heart. 'No way. I ain't going down there.'

'What? Why not?'

'I don't like the look of that thing, Joachim. It's bad news, I can feel it.'

'Don't be simple all your life, Corin. It's just a big rock, now come on.'

Corin shook his head vehemently and thrust the fire extinguisher he carried towards Joachim. 'Here. You want to go down there, then go, but I'm going back to the harvester. I'm going to vox Prandium and get someone to come out and pick us up.'

Joachim could see there was no arguing with Corin, and nodded.

'I'm going to take a closer look,' said Joachim. 'I'll be right back.'

Slinging an extinguisher over each shoulder, he picked his way carefully down into the crater.

Corin watched him until he reached its base and turned back the way they had come. He touched his wounded arm, wincing as pain flared just above his elbow: it felt broken. He glanced over his shoulder, hearing a loud hissing, like water being poured on a hot skillet, but continued walking.

The hissing continued, followed by an almighty crack.

Then the screaming started.

Corin jumped, spinning around as he heard Joachim shriek in agony. His friend's scream was abruptly silenced, and a keening screech cut the air, utterly alien and utterly terrifying.

Corin turned and sprinted back towards the harvester, fear lending his limbs extra speed.

There was an autogun in the cab, and he desperately wished he'd brought it with him.

He stumbled along the gouge torn in the earth, tripping on a buried root and falling to his knees. The thump of heavy footfalls sounded behind him. Something large and inhumanly quick was speeding through the corn. He could hear snapping stalks as it came nearer and nearer: Corin was in no doubt that it was hunting him.

He moaned in fear, stumbling to his feet and running onwards. He risked a glance over his shoulder, seeing a blurred form ghost from sight into the swaying corn.

The tread of something large seemed to come from all around him.

'What are you?' he screamed as he ran.

He ran blindly, bursting from the corn and yelling as he fell headlong into the irrigation ditch. He landed hard, cracking his elbow against the rockcrete, swallowing a mouthful of brackish water as he screamed in pain. He scrambled backwards, spitting water and shaking his head clear.

He looked up as a dark shape blotted out the sky above him.

Corin blinked away the water in his eyes and saw his pursuer clearly.

He drew breath to scream.

But it was on him in a flurry of scything blows that tore him apart before he could give voice to it.

A lake of blood spread from the dismembered corpse. Corin's killer paused for the briefest second, as though scenting the air.

It scrambled easily up the slope of the ditch and set off in the direction of Prandium.