The going was harder than he had realised, or the building was deceptively far; after ten minutes of laboured, silent walking they were still some way away. Although the great shape above them still blotted out the sun and filled the land with a deep shadow, it was still warm and humid, and they were soon sweating and uncomfortable.

The other fish was totally stationary, either indifferent or biding its time. Marcus found he had to make himself stop looking at it, given how treacherous it was underfoot.

No one wanted to talk beyond muttering curses as they tripped over weeds and molehills. A tight silence stretched between them, each lost in their own thoughts. Marcus was mulling over the situation, trying to work out what to do. He still couldn't shake the idea that this was some kind of stitch-up; and, if it was, someone would pay for his damn car. The alternative, that he'd just watched someone be hunted and killed by space aliens, seemed impossible. And yet...

The building was a hundred yards away or so. Now he was closer, it didn't seem so much like a stables as a little cottage, although it was hard to tell after years of neglect. It was also further away from the wall than he had thought.

Leona fell into step beside him.

'What do you think?' she asked, quietly.

'Not sure. If there is something we can use to make a bridge we might be able to get over. Don't think jumping would be that safe.'

'I agree. It looks like it was built far enough from the wall to stop people getting in that way.'

He glanced behind him, at Ben who was a struggling to keep up, and at Tamsin who had gone some way ahead; then, he continued, whispering.

'What did we just see?'

Leona shook her head.

'I don't know. This is either a sick joke or something really weird is going on. You were closer than me: did it look like a fake?'

'Hard to tell. I mean, what would a fake look like? I couldn't see any mirrors or wire if that's what you mean.'

'No. Me neither.'

They trudged on in silence, Marcus swatting futilely at the clouds of mosquitoes that surrounded them. Suddenly, someone's phone started ringing, the high, clear sound cutting through the stifling quiet.

They both looked around. 'Not me,' said Leona.

'Nor me,' replied Marcus.

Wordlessly, Tamsin turned round to face them, and held up her handset.

'Well, go, on then...', said Marcus, but Leona stopped him.

'Hold on. What is it, Tam?'

She walked forwards, her face expressionless, the phone trilling in her hand. As she reached them, Ben puffed up.

'What's going on? Who's calling?', he panted.

Tamsin shrugged.

'It's Stuart.'

Marcus gaped at her.

'That's ridiculous... well, I guess it shows that this was a stitch up, after all. Were you in on it?'

There was a silence.

'If you don't answer it, I will,' he continued, belligerently.

'I don't think that's a good...', started Leona, but Tamsin silently slid her hand across the touch screen, and tapped the speaker phone symbol.

'Hey, Tam! How are you doing?'

Stuart's voice was distorted by the poor signal, but it was recognisable.

'Stuart, what happened to you? If that was a joke, it wasn't very funny,' Tamsin calmly replied.

'I'm fine; it was just an accident. I'm just up by the house.'

'Are you injured? It looked a bit ugly.'

'No, I'm totally fine, really. Just a bit bruised! You should come up here and see, though.'

Leona touched Marcus' arm, and pointed towards the last fish thing. It had started gliding down towards them.

Ben followed her finger, saw it too. 'Tam, I think you should hang up.'

'Ben, is that you?', asked the voice of Stuart, obviously able to hear them all.

Tamsin ignored them all, and kept speaking into the phone.

'Stuart, take a photo of yourself and send it to me. I'm worried that you might be injured. I need to see it so that I can call an ambulance. I think you might be in shock. It will take me some time to get up there.'

'Tam? Really, I'm, fine...'

The machine had covered maybe a quarter of the distance now.

'Come on Stuart. I know what you are like. Remember how you were when you fell through that window.'

'It's not like then; anyway, I think my camera is broken...'

Tamsin tapped the screen to cut the call, and in a single fluid movement hurled the phone as far as she could. It flew a dozen metres and landed in the overgrowth. It started ringing again almost immediately.

She looked at them.

'I think we should run now.'

They hurried for the building, as it seemed to be the only place to run to. Behind them, they saw the fish machine drifting onwards.

'There never was a window, was there?', asked Leona, panting as she pounded across the rough grass.

'Of course not. And anyway, he managed an entire conversation without swearing.'

They were nearly at the doorway of the building. Even though there seemed to be no door, it was hard to tell what was inside; the windows were overgrown or boarded up, and so the inside was dark, even compared to the shadowed landscape around them.

'You think they are following our phones, too, right?', asked Leona.

Tamsin nodded. 'Yes. It's what happened to the woman from the cult: one of those things got her while she was phoning someone.'

'Right, and Stuart, too. Better turn off mine, then.'

'Yeah. I'll get Ben to switch his off, and you tell your boyfriend.'

'Sure.'

Even though he was jogging in stifling heat in twilight from a space death thing, he couldn't resist a smile at the fact that Leona hadn't contradicted Tamsin about being his girlfriend.

They hurried through the low doorway; Marcus was first, followed by the two women and with Ben last, looking pink and flustered. As soon as he was in, he strained his eyes in the dark, trying to work out what kind of place this was and whether they could use it to their advantage. He pulled his phone out, intending to use it as a light; but then remembered what he'd heard, and powered it off instead.

It must have been some kind of cottage. It had a bare flagstone floor, uneven and treacherous, with piles of leaves around the edges. There was no furniture, although there seemed to be a fireplace in the far wall, again full of vegetation. He could see another room, darker than this, and he cautiously made his way towards it, eyes still not used to the gloom.

Ben slumped in the corner, exhausted, and he heard Leona and Tamsin quietly talking as they stared out the doorway back to the thing following them.

'Look, it's gone to where you threw your phone.'

The second room was about the same size as the first. Squinting into the dark, he thought he could make out a pile of something in the corner, and he started shuffling towards it, trying not to pitch over on the uneven floor.

'It's stopped again. God, that's a relief.'

It looked like it was a small pile of gardening tools: pruning shears, a spade, a rake. He picked up the shears and the spade, wondering if they would be any use. Better than nothing, he thought.

'What the fuck? What's it doing?'

He started, and hurried back to the others as quickly as he could.

'Someone must have their phone on. Ben?'

'Not me.'

'It must be Marcus. Shit. I'll go and tell him. Marcus, where are you?'

'I'm here.' Ben was still sitting, Leona and Tam crouched either side of the door. 'It's not on. I turned it off already.'

'There must be something else...', muttered Leona.

'Come on, come into the other room. It's darker in there.'

'With no way out.'

'Got a better plan?'

'Maybe. Someone must have something broadcasting. An iPod, a tablet, something...'

Tamsin looked at them both.

'It's nearly here.'

'Right,' said Marcus, 'Plan B. We stand on either side of the door, and when it comes in, we twat it. Questions?'

Leona stood up, took the spade from him, and kissed him on the cheek. It tingled where her lips had touched him.

'Yes. But they can wait.'

He stared at her, astonished, held by her gaze; but then he saw how far away the thing was, so he took his position opposite her. Tam backed away from the doorway, Ben pulled himself to his feet, glanced into the adjacent room.

'Are there any more of those tools?'

'Yeah, a rake, I think.'

'Ok, I'll get it...'

'Too late...'

And at that point it floated through the doorway.

Now that he was only a foot away from it, he realised that it moved deceptively quickly. It had a very gentle iridescence to it; a subtle, pale blue shimmer even in the darkness of the cottage. It was also far more intricate than he supposed, with tiny grooves running all over the great shell-like sections that made up its body. Its insectoid limbs hung loosely below it, and he could see the tip of the harpoon just poking out of the end of its featureless head.

Leona and he hit it more or less at the same time, the rusty metal slamming into its flanks. Not only did they barely affect it – it bobbed slightly under the impacts, but that was it – they didn't even make a particularly loud noise, just a dull thud, not the clang of metal on metal he had been expecting. It ignored them completely, and continued to sail into the room.

Tamsin backed away, pressed herself against the wall, trying not to move; it glided towards her, but then abruptly turned and headed towards the entrance to the other room.

'Jesus, Ben, it's coming for you!' She screamed at Marcus, 'can't you stop it? Hit it! Kill it!'

Leona took another swing at its tail, but it just flicked her away, obviously unconcerned. Marcus tried to club it, but the shears were the wrong shape to be effective anyway, and the blades simply slid of its top.

'Ben, you must be carrying something, something that's sending a signal!'

Marcus lunged forward, and grabbed its tail fin as best as he could. He was expecting it to be slippery; but instead it felt like holding rubber, tactile and slightly resinous. He found he could grip it with ease, but also, he could do almost nothing to stop it moving forward.

He felt a shiver in it, and suddenly the limbs were extended. From his vantage point, he could see long, smooth knives hanging from its claws, knives and needles that flexed and swayed as it moved.

They were only a few metres from Ben now. He was staring at them, wild eyed, holding the rake as if it were a pike. As Marcus was dragged along, he watched Ben jab forwards with it; the thing caught the rake head with a forward claw, snatched it from his hands, discarded it. Ben whimpered.

Marcus has an idea, and brought the shears up, manipulating them as best as he could in his right hand while he hung on with his left, trying to find a crack in the thing's armour that he could wedge them into, maybe break something internal.

Tam was screaming at them both, begging them to think of something; Ben was crawling backwards, towards the corner of the room, shaking with fear. Suddenly, as he moved, Marcus noticed a flicker of light at his chest...

'Your camera! It must have something...'

Ben stripped it from around his neck and threw it into the opposite corner. It skidded across the floor, shedding shards of plastic as it went, winking red lights spinning crazily.

The machine immediately flexed itself towards it; as it turned, an opening between shell sections widened, and Marcus shoved the shears into it. There was a grating noise as the rough metal sank into the machine, followed by a squelch; and then dark, stinking liquid started to pump from the opening, smearing itself across the shears and his hands.

The thing started to thrash; it threw him off and he landed painfully on the hard floor, the breath knocked from him. It arced round to face him, the fluid streaming everywhere; its talons were forward, the length of the knives terrifying now they were pointing to him; he tried to scramble away, but it was too fast...

And then there was a thud, and it was writhing on the ground and Leona was standing above it, holding the spade. She had smashed the head of the spade into the handles of the shears, driving them further into it, deep into whatever internals it had.

He rolled away from its flailing limbs, scrambled out of the door with her and Ben, out of the hut, back into eclipsed daylight, running as fast as he could. The four of them scrambled as quickly as they could across the rough ground, watching as a fleet of tiny machines descended from the vast shape above them. They ran because they thought that this was the end, revenge for the death of the fish machine in the hut behind them; but the tiny units ignored them, and instead retrieved the twitching corpse, bearing it aloft between them, flying back towards the metal sky. Marcus slowed down, and stopped, watching it, and so he saw the moment when an iris opened, and the little fleet disappeared into the ship. And then, with a gentle sigh, the ship was gone, the wind rushing up to fill the space it had suddenly vacated, making the grass and trees wave as if they were bidding it farewell; and the sun filled the sky again, and they were squinting in the brilliant light.

The four of them stopped, pulling great lungfuls of the warm air, collapsed on the grass.

'Holy shit,' panted Leona. 'Glad to see the back of that.'

Marcus walked up to her.

'Hey, thanks for saving my life. Or something.'

She reached up, and kissed him briefly on the lips.

'You're welcome. Wanna get a drink? I think I could do with one.'

He laughed, exhausted and delighted.

'Is this a date?'

'Not until you clean some of that stuff off you: you stink.'

'It's eau d'abduction. A fragrance for him and for her.'

He looked at his hands, covered in the sticky purple stuff from the fish machine, and then at her filthy, torn clothes, her disarrayed hair, her smiling face. She lifted her hand to her cheek, discovered a gash, frowned slightly.

'Think I could do with freshening up a little, too.'

Tam and Ben came up to them, also breathless, relieved.

'What now?'

He realised that they were looking at him and Leona for guidance, and he shook his head, too tired for inspiration.

'I dunno. Get the SatNav from my car. Walk back up to the house, see if Stewart is there. The real one. Maybe we can use that woman's car. Get somewhere with reception. Dunno what we do then... Anyone think of anything better?'

Ben shook his head; Tamsin just stood there, and slowly, gently, started crying.

The SatNav was remarkably still intact; and eventually they all set off up the hill, exhausted by it all, Ben comforting Tamsin.

'I think we've all learnt something today,' he said quietly to Leona as they held hands, strolling up the dilapidated drive, her touch sending thrills through his palms, tired but happy.

'That's right,' she replied. 'If you see a space alien, hit it with a spade.'

He laughed.

The SatNav in his hand beeped once, and, unbidden, turned itself on.