When I first heard the rumour that there might be a refugee camp at Gunwharf, I imagined orderly rows of white tents and medical teams bustling around helping the injured and infected.

I did not expect the tableau of death and despair laid out in front of me.

At first all we can see are the bodies.

They line the plaza on each side of us, stacked seven or eight high and at least that as deep. When the Red Death first broke out, people treated the dead with the same respect as they had before the Waves, before the Others. They wrapped victims in sheets and blankets, doing all they could to preserve their dignity and honour their memory. None of these bodies are wrapped in sheets. There's no time anymore; people are dying faster than their bodies can be wrapped, and besides, there aren't enough sheets. These bodies aren't even arranged with any semblance of respect, just tossed on top of each other like discarded mannequins, their limbs all bloated and tangled together, the flesh of their bodies grown soft and putrid, bursting open where they press up against each other. The stench is eye-watering, mingled with the greasy stink of smoke from the bonfires that I can't yet see. There are too many bodies to burn.

Why did anyone think there was help here?

Why did I listen to a stupid rumour and drag Lola all the way up here?

Desperation drove me to this point. There was precious little food or water left to scavenge in Havant, the Red Death was creeping in on a bloody tide, and savage gangs were converging on the outskirts of town. It wasn't safe there anymore. But it's not safe here.

Behind her mask Lola coughs, her eyes watering with the sting of smoke in the air. I pull her against me, shooting her a warning look. In these plague-ridden times, it's not a good idea to be caught coughing. That's usually how the Red Death first rears its head - a rattle in the lungs that becomes a fever-boiled brain and literally vomiting up your guts.

I want to turn around and flee from this awful place, flee from the nightmare that I foolishly hoped would be our salvation. But Lola is exhausted and hungry. Before the Others came, Gunwharf was one of the most social spots in Portsmouth, hosting countless restaurants and cafes amongst all the shops and nightclubs. With such a dense cluster of places to eat, there has to still be food somewhere. I have to believe that, or this journey has been wasted, and my sister and I are cast adrift on a sea of uncertainty.

Lola squeezes my hand, her face blanched with fear. There are plenty of people still alive here, but none of them pay us any attention. Their faces - what I can see of them above the rag-masks they wear to protect their noses and mouths from the threat of infection - are smoke and sweat-streaked, their eyes hollow and haunted. We're just two more bits of flotsam washed up in the aftermath of the worst disaster ever to befall our planet. There's a palpable sense of fear and hostility here, thick on the air amid the rotting flesh stench.

I crouch down in front of Lola, my hands on her arms. "We're just going to stay a little while, okay? Just to get some food and water."

She doesn't say anything, but tears swim in her eyes, and I get the feeling her lips are trembling behind her mask. "I don't like it here," she says.

"I don't either." But if I don't keep her fed and watered, Lola will starve to death or die of thirst, and then I'll be just like that woman on the motorway, left holding the body of someone I love and crying for help that will never come. It won't take long to find out if there's food here. But first I have to find somewhere safe for Lola to stay, just for a little while. Once we have supplies we can hit the road again. I don't know where we'll go, but surely anywhere's better than here.

"Hey!" A loud, aggressive voice cuts through the buzz of despair all around us, and I quickly straighten up, placing myself in front of Lola.

A man strides towards us, two other guys flanking him like bodyguards. As he draws closer, I wonder if maybe boy isn't a more appropriate word to describe him - he can't be more than a couple of years older than me. From a distance, with a scruff of beard starting to sprout along his jaw, and his face streaked into lines by smoke, he could pass for older.

He stops in front of me, looking me up and down. I do the same, assessing him. He might not be much older than me, but there is a hard cast to his features that makes me wary. He looks like the kind of person who has survived the Waves by jettisoning his humanity.

"Name?" he snaps.

"Excuse me?"

"Name!" He shouts it this time, and I flinch.

"Maddy Smith. This is my sister, Lola."

He looks her up and down too, or as much as he can with her mostly hidden behind me.

"Are you infected?" he snaps.

I shake my head. "We're both clean."

He nods, a curt motion. "Good. I'm Luger, the guy in charge around here."

Looking at the carnage crowding in on all sides, it's hard to believe that anyone is in charge. But I don't say that. I don't know what sort of person Luger is, but there's no sense making him angry.

"We thought..." My voice trails off as I look around at the piles of corpses; breathe in the foul stench that slides like oil down the back of my throat. "I mean, we heard there was help here."

Luger stares back at me. "Help?"

"A refugee camp." The words sound ridiculous now, and I regret them as soon as they leave my mouth.

One of Luger's henchmen snorts with bitter laughter, but Luger's expression doesn't change. I almost wish he'd laugh too, just so I could get some idea what's going on behind his flat stare.

"There's no refugee camp, there's no help. There's just us," Luger says. His voice is as flat as his eyes. At least he's not sniggering at me like his friend.

I'll never know where the refugee camp rumour came from. Maybe it was just wishful thinking that somehow solidified into possibility. It doesn't matter now. We followed a rumour and it's turned out to be a dead end. Now we have to deal with that.

"We don't have many rules here," Luger says. "There's no fighting, and you have to report anyone you think might be infected."

That isn't a problem. Life is difficult enough without picking fights, and we won't be here long enough to have to report anyone. I just nod.

Luger stands to one side, apparently satisfied, and I sidle past him, Lola clinging to the waistband of my jeans. Luger hasn't done anything untoward, but he makes me nervous. Maybe it's just because he's appointed himself in charge. People who simply choose to seize power automatically bring up my guard. But maybe I'm being unfair. Maybe Luger put himself in charge simply because someone has to be, and no one else volunteered for the job. I suppose it doesn't matter; we won't be here long enough to find out.

People glance at us as we pass by, but their gaunt faces register little interest. Lola presses to my side like a limpet as we make our way into Gunwharf Central Square, an open concrete space hemmed in on all sides by rows of shops, boasting a cinema at the furthest end. The cinema's glass-fronted facade has been reduced to a twisted metal frame; the orange VUE sign probably carried off with the waves and sunk to the bottom of the sea. A few shops still have odd windows more or less intact, and the glass is patterned with salt. Dried hanks of seaweed decorate wave-stripped trees.

But my eyes simply slide over all that before focusing on the thing that now dominates the square - the bonfire. It blazes in the middle of what was once a thriving shopping hub, a huge conflagration belching black smoke into the air. Through the smoke and flames I glimpse heaps of bodies, fat and flesh melting off blackened bones. I press Lola's face against my side so she doesn't have to see. I know it's a pointless gesture, but I can't help wanting to shield her from all this, to maintain her innocence for as long as I possibly can.

The smoke spirals into the sky, turning it black. Somewhere up there the mothership is hovering. I wonder what they think when they look down at us. Do they feel any shred of sympathy at the devastation they have wrought? Are they even capable of emotion? Or are we just insects to them, nuisances to be crushed as quickly as possible?

I hurry Lola past the bonfire, following the hollowed-out husks of shops around the other side of the square, towards the waterfront. I need to find somewhere for Lola to stay while I go in search of food. I don't trust these people. Now I can see how many mouths are here, there seems little chance of there being anything left to eat, and if I do find something, I have to be prepared for the possibility of fighting for it. Despite what Luger said about people not fighting, I'll do anything to keep Lola safe. But it seems safer to hide her somewhere than take her with me in this plague-riddled, miserable place.

It takes me a while to find somewhere I think is safe enough. It looks like it was a restaurant, fronted by a great empty space that must have housed windows; a bar curving along the back wall. A twisted jumble of metal-legged chairs is heaped in one corner, and a pair of mottled feet stick out from beneath the jumble. Behind the bar, a stainless-steel door opens into an industrial kitchen. I check every cabinet and every container, but all the food has long since been scavenged. I'm not surprised.

I guide Lola into a corner, pressing her back against the wall. Even the cutlery has been swiped, but at the bottom of one drawer I find an abandoned meat-mallet. I push it into Lola's hands, hoping that it's only ever been used to pound chicken or beef.

"I need you to stay here, okay, Lola? Stay very quiet and very still," I instruct her.

She pulls her mask down, her lower lip trembling. "Don't leave me."

"I'll only be gone for a little while," I say, forcing a smile I don't feel to my lips. "I'm just going to get us some food."

Lola shakes her head, tears gleaming in her eyes. Several of them spill over, cutting tracks through the grime on her cheeks. "Please, Maddy."

I take both her hands in mine. She's so tiny, so fragile, like she's made of glass. I'm terrified that this world is going to shatter her. "I promise I won't be long, Lola. But we need food and water." I wipe her tears away with my thumb. "And I need you to be brave for me, okay?"

She nods and snuffles. "Okay."

*

I wedge the door shut with one of the chairs from the corner, trying to put as much of a shield between Lola and the world outside as I can. It's not as sturdy as I'd like, and I resolve to be fast finding food. I don't want to linger in this place. Though I don't know where else we can possibly go.

The Tesco Express is my first stop, situated back near Vernon Gate. I'm not holding out much hope, but a supermarket is the obvious place to go and look for food, even in a post-apocalypse. As I suspected, every shelf in every aisle is picked clean. At the back of the shop, alongside the plastic bulk of a cash machine, a man lies groaning on the floor. When he sees me, his hand stretches along the floor, grasping for my ankle, but I step out of reach. His skin is flecked with plague-blood, red trickling from his eyes and mouth. I can't help him. No one can.

Leaving Tesco, I retrace my steps, back towards Central Square. If the supermarket has been picked clean, the restaurants and cafes will have been too. But there might still be popcorn or hot-dogs stashed somewhere behind the cinema counters. I have to check.

The cinema itself is located on the second level of shops that rings the square, accessed via a bank of lifts, a flight of stairs, or an escalator. The lifts don't work anymore, and the stairs are even more clogged with bodies than the escalator. Escalator it is then. I head for it, averting my eyes from the raging bonfire. Not looking at it doesn't block out the smell; it soaks through my rag mask, filling my mouth with the taste of rot.

I try to be as careful as I can climbing over the bodies that lie on the escalator, but I still wind up trampling someone underfoot. The way into the cinema used to be marked by glass doors, but those are gone now, reduced to shattered, shining shards on the floor.

I hesitate before heading in, remembering this place as it was before the Others came, when it was filled with throngs of people talking excitedly about whichever film they were going to see, the air rich with the smell of melted cheese and popcorn. The Others have taken so much from us, our entire way of life, everything we once took for granted.

I give myself a shake, sloughing off the painful nostalgia. There's no time for it now, not when Lola's waiting for me to get back.

Inside, the cinema is a ruin, and I try not to look too hard at the advertising screens scattered across the floor, the tatters of promotional posters still clinging to the walls. Before I get too far into the room, I can see the counters are both popcorn and hot-dog free. I'm not the only one who's had this idea. But I progress further, and notice something that fills my heart with joy. On the right side of the room, alongside what used to be the ice-cream counter - also empty - the wall is lined with plastic boxes of sweets. There are empty spots in the display where invading waters must have smashed several boxes off the wall, but some of the remaining containers still have brightly coloured sweets inside. It's hardly nutritious but it has to be better than nothing.

The paper cups that cinema-goers used to fill up with sweets have been washed away, but when I put some muscle into it I manage to wrench one of the boxes off the wall. It's filled with bright coils of gummy snakes. They can't have escaped the waves - these boxes are hardly watertight - but I figure the worst they'll be is a little salty. I don't have much choice. There's no more food here, and every second I'm away, Lola's on her own.

With the box tucked under my arm, I make my way back to the kitchen where I left Lola. I try not to meet anyone's eyes as I go, and I do all I can to keep the sweets hidden. I'm afraid that if someone sees them they'll try to take them from me.

I make it back to the kitchen without incident. As I pull the chair away from the door, it occurs to me that I should have arranged some sort of code-knock so Lola knows it's me coming back and not someone trying to break in.

The smell of smoke is thick and heavy in the kitchen, and when I get in I realise why. There's a window set in the far wall and Lola has opened it, letting in tendrils of smoke.

"Lola?" I say.

She turns to me, a smile on her face. I haven't seen her smile like that since before the 1st Wave. A pigeon is cupped in her hands, softly cooing. Dumping the box of sweets on the nearest countertop, I cross the kitchen towards her.

"What are you doing?" I exclaim.

Lola holds the bird up as if I haven't already seen it. Her face is beaming, so bright and happy that it makes my heart ache.

"Put that down," I say. "Pigeons carry diseases."

No disease from a bird can begin to touch the horror that is the Red Death, but I'm not going through all this to keep Lola plague-free, only to let her pick up some disease from a pigeon.

Lola's face falls, and now I feel awful for taking away that tiny piece of happiness. But her life is worth too much to risk. She's all I have left.

Placing my hands under Lola's, I guide them back to the window and gently open her fingers. The pigeon doesn't move, sitting contentedly in Lola's palms, so I flap my hands at it until it spreads its wings and flies out of the window.

"Bye," says Lola softly.

Looking at the smear of pigeon crap on her hands, I tut.

"It's okay, I don't mind," Lola says.

"I do," I tell her, and wipe the crap away with the corner of my t-shirt.

There's nowhere in the kitchen that's particularly comfortable so I choose a spot for us in the furthest corner, one where we can see the door. I want to be able to see if anyone's coming.

I pull Lola into my lap and feed her gummy snakes, telling her the story that our mum used to tell me when I was very small, about a princess plagued by the hardness of a pea through multiple mattresses. Lola is suitably enraptured, but my mind keeps wandering, my words coming out on autopilot.

Where will we go once we leave Gunwharf? There's no way we can stay, not with the plague running wild. But if there's no refugee camp here then I can't believe there's one anywhere. Portsmouth is the most densely populated city in the country, so logic dictates that help should arrive at the place where the most people need it. But help hasn't arrived, and if it hasn't come by now, so many weeks after the Waves started, then I doubt it's ever going to come. That means it's Lola and me against the world. I'm responsible for her now, and I will be for the rest of my life.

That terrifies me.

Partway through the story, Lola falls asleep, her breath tickling my collarbone, but I carry on telling the story anyway, because the sound of my own voice is better than the crackle of flames and moans of the dying outside.

At some point I must have fallen asleep for the next thing I know, I'm opening my eyes. Pale light slants in through the window behind me, that ghostly greyishness of early morning. I've actually slept through the night, my exhausted, starving body giving itself up to dreamless black. Lola's still in my lap, and my legs are numb beneath her. I try to move them without waking her, try to get the blood flowing again, but the shift in her breathing tells me she's awake.

"Maddy," she mumbles. "I don't feel well."

"Probably from all those gummy snakes," I say.

She coughs and my stomach plunges into my shoes. I put a hand to her forehead. Lola's skin is burning hot and clammy, beads of sweat turning her hair damp. I tilt her face towards mine, and tears of utter heartbreak sting my eyes as I see the sallow skin, the bloodshot eyes, the blood-drops already forming between the cracks of her lips. There's no mistaking it.

My darling Lola has the plague.