Something was scratching at my face, pulling me out of a dream where my mouth was full of razor sharp shards of glass and I was chewing on them, feeling the agony of every bite and the blood pouring into my throat, congealing there, choking me with fat, bloodied lumps of gum tissue.

I blinked, groaning, as slumber left me and I swatted at whatever it was, scrambling to sit up in alarm when my hand met with a target much larger and furrier than I had imagined it might be.

The rat that had been investigating my face squeaked as it rolled onto the ground, immediately heading towards the safety of the wall on the far side and scampering away, its long worm-like tail trailing through the puddles of dank water behind it.

I rubbed frantically at my cheek, feeling for bite marks, even though I knew that it was stupid to think I had slept through a rat gnawing at my face and that it had just been its tiny clawed feet I had felt, scratching at my skin. Another rat skidded past my foot, barely even caring that I was there as I launched a half-kick at it, shooing it away. It joined the other and it was then, as the fog of sleep cleared and my eyes adjusted to the dark, that I saw them all.

Slick, brown bodies tumbled over each other, their long tails glistening in the wash of moonlight that somehow managed to penetrate the shadows under the bridge where Alice and I had made our new camp. I pushed my back up against the wall as they streamed past me, a constantly moving, putrid tide of vermin, a dark river with eyes that glinted yellow. I could hear them, despite the ever-shifting rumble of traffic from above - the city never slept - and their high-pitched squeaks sounded like the panicked shrieks of wounded animals, all desperately fleeing some oncoming threat.

City rats were braver these days, living off the growing piles of waste accumulating anywhere people could dump their rubbish, breeding like never before, and with little fear of the two-legged giants supposedly in control. Seamus said he'd read a book once about giant rats taking over the city after the nuclear bombs had dropped and the whole world went to shit, and that he figured we were probably half-way there already and that the rats knew it too. That's why they didn't hide much anymore, he'd told us, they were getting ready, testing the murky waters, so to speak. He even reckoned he'd heard stories about a fella down in Walthamstow who fell asleep one night, high on smack, and woke up to find loads of them eating him alive. 'He lost three toes on his left foot', he said, lowering his voice over-dramatically, like we were kids and he was telling us a scary bed-time story, 'two fingers on his right 'and, and part of his ear. Lucky he didn't get the bloody plague, too, I reckon.'

Alice said Seamus had drunk so much high-strength booze over the years that his brain probably had the plague, but I'd always wondered whether he might be right. Giant rats and nuclear bombs didn't seem that far-fetched to me. After all, as far as I could see, the world had already turned to shit a long time ago.

I turned to nudge Alice next to me. She had to see it, she had to see them, if only to prove that my brain hadn't succumbed to Seamus' plague too and that what I was seeing was real. The streets could do that to you. Little by little, gnawing away at whatever reality still existed for you out here, chewing on the bone and gristle of your mind, until at last - chomp - it was all gone, and you were like Seamus or the others, who spent more time drunk on cheap booze and off their tits on smack, because it was just better that way. It was better than facing what was real. Better than acknowledging you were fucked. That life was fucked. And that it would always be like this.

'Alice,' I said, 'Alice, you have to...'

But Alice wasn't there.

I stood up, pushing off the dirty, worn sleeping bag that Seamus had given us, after he'd managed to get himself a new hand-out from down the drop-in centre.

'Alice? Alice?' My voice bounced off the walls of the tunnel, the sound not too dissimilar to the panicked squeaks of the swarming rats as they ran.

The rats. They were running from something.

What if that bloke had found us? What if him and his mates had Alice now and the rats were running from that, fleeing from the giants that had disturbed them from their hidey-holes in the shadows down here?

I ran then, tripping over rats that still streamed this way, calling her name over and over and feeling the nausea twisting like vines in my stomach with every step. Following the tunnel to the end, I found myself in the alley that led from the industrial estate to under the bridge, all overgrown with thorny bushes and nettles that you had to fight your way through like you were an explorer hacking his way through thick jungle.

The rats were still coming. I could hear them, could see the slits of their amber eyes in the constantly shifting darkness. Just before I reached the end of the alley, I must have caught one under my boot. Its high-pitched squeal made me lose my footing and I stumbled, landing hard just inside the mouth of the alley where the shadows weren't so dense.

Sprawled on hands and knees, I looked up, feeling the sharp sting of the graze on my palms where I had tried to break my fall.

A rat stared back at me with dead, vacant eyes.

Its body was torn open, revealing nothing much left inside but an empty bloodied cavity where flesh and organs had once been. Despite there being barely half a carcass left, in life, it must have been about the size of a small cat, not including the tail, which lay limp on the ground behind it.

Not far from where the dead rat was, another one lay also dead, this one not so large and torn in two, both parts of its body similarly stripped of the fleshiest bits, and what was left of the severed cadavers now empty. Still on all fours and feeling a freeze that had nothing to do with the winter night's temperature, my eyes followed the path of dead vermin and blood, the grim realisation of just why the rats had been fleeing becoming all too horribly clear.

Something had attacked them. Fed upon them.

A dog maybe. A stray cat, or pack of strays even. There was a few that often slunk around together near the warehouses on the estate, horrible mangy-looking things, all protruding bone and matted fur, trying to catch the rats that inevitably lurked nearby, feasting on any scraps they could find.

A sound echoed from across the yard, something shuffling in the gloom where the trail of dead rats disappeared into the darkness. The area next to the first warehouse was steeped in impenetrable shadow. The security light never worked properly and was temperamental to say the least, the sensors seeming to have a mind of their own and deciding when to illuminate the yard and when to let it languish in darkness.

'Hello?' I called out, immediately regretting it. Why did we do that? Why did we call out in the darkness when we didn't have a bloody clue what monsters might be waiting there for us?

I stood up, ready to run, ready to flee with the rats.

This was stupid. I was being stupid. This was real-life, not some bloody horror movie. What did I think was going to come lumbering out of the dark?

Wet, squelchy sounds drifted on the air. A foot shifting on the concrete. It wasn't an animal. It sounded too big to be a dog or a cat.

I'd never imagined I could be one of those people who pissed themselves out of sheer fright. Or fainted. And right then, I could imagine doing both. A guy like me would never play the hero in a horror movie. I was one of the ones always destined to meet some grisly end at the hands of the depraved killer. The one everyone looked at on screen and would say, nodding with glee, yeah, he's next, he's definitely next.

My breath was ragged, painful, as it rasped in my throat. 'Fuck this,' I whispered.

I moved and one tiny step was all it took.

The security light came on with a flash; brilliant white light blinding me, and for one second, I squinted and threw my hand up to shield my eyes from the floodlit glare. As the white spots in my eyes faded, I saw it through my splayed fingers. I saw the monster. The rat-killer. The creature from the horror movie that lurked in the shadows, now bathed in light.

And it was beautiful.

Dirty-blonde hair. Delicate fingers. Perfect mouth.

Alice. My Alice, crouched low on her haunches, blood dripping from her mouth – God, I loved kissing that mouth – a rat, squirming and struggling in her beautiful hands. She blinked in the glare, her eyes watching me warily, before blinking again, and, as if I wasn't even there, as if I wasn't standing right there looking at her, she raised the tiny animal to her lips and bit down. Teeth tore into the rodent, ripping its flesh from its body, cramming as much of it into her mouth as she could. A piece of something, soft and wet, fell to the ground, and her fingers found it, shoving it greedily back into her waiting mouth. She chewed it, whatever it was, innards or flesh, her jaw working, her lips slapping together with satisfaction, her eyes glazed in ecstasy.

Like it was the best thing she'd tasted in a long time.

Like it was the best, damn thing she'd tasted in her whole life.