We don't get very far. This corridor stretches along the side of the gym. We hurry to the end of it and start down the next passageway, off of which lie a series of classrooms. But we're less than a quarter of the way along when we hear a mob racing towards us, screaming and wailing.

"They must be heading for the exit or the gym," Stagger Lee says.

"They'll be on us in a sec," Copper mutters.

"We have to tell them to go back," Suze pants.

"Don't be stupid," I snarl. "They're being chased. They won't stop and listen calmly."

"We won't get through them," Cass says.

"Even if we do, zombies must be right behind," Copper says.

There's a door to my left. I open it and glance into a small classroom for younger kids. It's empty.

"In here," I decide. "We'll hide, wait for them to pass, then sneak out."

"What if the zombies smell us?" Cass asks.

I shrug. "It's a gamble one way or the other."

The first few kids of the mob surge into the hallway. Zombies are among them, snapping, tearing, maiming, killing. "In!" I bark and everyone pushes into the room after me, no complaints.

When we're all inside, I slam the door shut. There's no key, of course. "We need to barricade it," I shout, but some of the others are ahead of me. Copper and Ballydefeck arrive seconds later with a desk each, which they prop against the door. More furniture is added to the pile and moments later there's a mountain of desks and chairs between us and the door.

"Won't do much good if they come through the windows," Trev says, nodding at the frosted glass on either side of the door.

"They can't see us through the glass," I mutter, stepping back. "And if we keep quiet, they can't hear us either."

"What about smell?" Cass asks.

I frown. "What is it with you and zombies smelling us?"

"I've seen movies where they can sniff out the living," he says.

"Well, let's hope they all had really bad colds when they were turned," I growl and we all squat quietly.

Screams in the corridor. Sounds of fighting. Someone slams into the glass and it rattles. At first I think it's a zombie trying to break through, but it must have just been someone crashing into it, because there aren't any more assaults on the window.

"Please don't eat me!" I hear a kid beg. "Please don't eat me! Please don't - "

A high-pitched shriek. I shut my eyes and feel tears build behind my eyelids. This can't be happening. Zombies aren't real. Pallaskenry was a joke. We were so sneery, laughing about it in class, coming up with alternative theories. I must be dreaming. Babies will come crawling over the desks any minute now, calling me their mummy, and I'll know it's a nightmare.

But that's wishful thinking. This is reality. I always know when I'm having a dream. No matter how real it seems at the time, it never feels completely real. This does.

I open my eyes and look around. Everyone's shaking and either crying or close to it. La Lips is clinging to Copper, weeping as he whispers soothing words in her ear. Linzer's praying. She's not the only one - Dunglop, Tyler, Ballydefeck and two of the Muslims are also openly praying. I figure some of the others are too, but privately.

Pox is squatting a couple of feet away from the rest of us, weeping over his wounds, shaking his head, muttering something under his breath. Cass is keeping an eye on him, flick knife open and glinting, ready to leap on Pox at the first sign that he's turning into a zombie.

"You know the worst thing about this?" Elephant whispers. When a few of us stare at him, he says glumly, "It ruined my comeback."

I stifle a giggle. "Idiot!" I snort.

"You were crap anyway," Meths says.

"Was not," Elephant growls.

"We need a plan," Trev says, and we look at him expectantly. "We can't just go charging about the place."

"So what should we do?" Cass asks.

"Stay here," Trev says. "Keep our heads down. Wait for the police to find us."

"But in Pallaskenry - " Copper starts to object.

"This isn't Pallaskenry," Trev snaps. "It's a school. They're not going to stand by and let soldiers kill a load of kids. There'd be riots if they did. They'll come as soon as they can, flush out the place, protect the survivors. If we can stay hidden for an hour or two, that's all we'll need. Maybe less."

We consider Trev's plan.

"If police and soldiers raid the school," Linzer says, "we'd be safer here than out there. They shot anyone who moved in Ireland. They won't know who's a zombie and who isn't, and they won't want to take chances."

"It'll be a free-for-all," Copper agrees.

"But if the zombies find us first..." Stagger Lee mutters. "I say we make a break for it. Head for the stairs, get to the floor above, find the exit, let ourselves out, don't look back."

"What if that door's shut too?" one of the Muslim boys asks.

"It won't be," Stagger Lee says.

"The one by the gym was," the Muslim reminds him.

"That was bad luck," Stagger Lee says. "There's no chance that two of the exits will be jammed at the same time."

"Who says it was luck?" the Muslim asks. "Am I the only one who thinks this is too much of a coincidence? The janitors check those doors regularly - they have to be sure they're working, in case of a fire. And on the very day we need them, one just happens to be stuck? I don't buy it."

"What are you talking about?" Trev snaps.

"Someone sealed it shut," the Muslim says. "We've been locked in."

A scary silence settles over us. I find myself looking at Cass, and he looks back at me. His eyes are wider with fear than they were a minute ago.

"What's your name?" I ask the Muslim.

"Seez," he says.

"Seez, do us all a favor and shut up," I tell him.

"Why?" he scowls.

"If you're right, we're screwed," I say evenly. "So let's not think about it, and keep our fingers crossed that you're wrong."

"But - "

"If we're locked in here with a pack of rotten zombies, what good will worrying about it do us?" I challenge him.

"We can come up with a plan," he says.

I laugh bitterly. "If someone's blocked all the exits, there's no plan, we're done for. We have to believe that the door back there was a one-off. If it wasn't, we'll find out soon enough, and we won't have to worry about it for long."

Seez stares at me, then nods reluctantly.

"So what do we do?" I ask. "Hole up or try for the exits? Let's vote. Who wants to stay?"

Everyone looks around, hesitant to be the first to vote. Then Linzer sticks up her hand. A few more start to rise. But before a decision can be made, Pox groans, turns aside and vomits.

"Gross," Dunglop chuckles - he's closest to Pox.

There's a strange creaking sound, like a plank being bent to snapping point. As I'm trying to place it, Pox shudders, then falls still. The noise comes again. Cass takes a cautious step towards the motionless Pox, rolling his knife lightly between his fingers.

"Everyone stay back," Cass says. "I'm gonna make sure - "

Pox lurches to his feet, leaps at Dunglop and bites a chunk of flesh out of his cheek.

Dunglop screams and staggers into Cass, knocking him aside. Pox is already moving. He scrabbles after Rick, the kid from a lower year, and grabs his foot. Rick kicks out but Pox bites into his ankle. As Rick screams, Pox turns on Suze and goes for her throat.

Cass gets in the way and jabs at Pox with his knife. Pox lowers his head and charges. I tackle him before he connects with Cass. Drive him sideways. He crashes into a desk and goes sprawling.

"Clear the bloody door!" I roar. As the others hurry to the piled-up desks and chairs, I face Pox, who's back on his feet, snarling. There's a strange green fungus growing over the places where he was bitten by the zombie. Only thin wisps, but I note their presence like some supersleuth with a keen eye for detail. And his fingernails are longer than they were.

No... hold on... those aren't nails. Bits of bone are sticking out of each finger, scraps of flesh and nails shedding from them. I recall the creaking noise and put two and two together. The bones must have lengthened and snapped through his flesh as he was changing. I glance down and spot bones sticking through the tips of his shoes too.

Pox closes in on me but is distracted when Cass whistles.

"Here, boy," Cass growls, beckoning Pox on. "Come and get it."

Pox scowls and goes after Cass, moving speedily. Cass stabs at him. The blade sinks deep into Pox's chest. It pierces his heart, but that doesn't matter to Pox. He pushes on and Cass goes down. Pox opens his jaws and snaps at Cass's face. His teeth are longer and thicker than I remember.

One of the Muslims grabs Pox before he can bite. Pulls him off of Cass and pushes him away. Pox falls, but one of his bony nails scratches the Muslim's chin and draws blood.

"We're out of here!" Trev shouts, and I see that the door is open. Everyone's spilling into the corridor. Meths is dragging Rick, and Dunglop is stumbling after the others.

"Let me help you," I pant, taking Dunglop's arm.

"Thanks," he moans, holding a hand to his bitten cheek.

"I'm so sorry," I whisper, then whirl swiftly and send Dunglop flying across the room. He smashes into Pox, who goes down again and starts biting instinctively.

"What the hell!" Trev shouts.

"Meths!" I bark. "Leave him."

Meths looks at me uncertainly.

"They were bitten," I growl. "The same thing that happened to Pox will happen to them."

"No!" Rick screams. "Don't leave me! I won't change! You can't just - "

"B's right," Copper says.

"Look," La Lips groans, pointing.

Pox is tucking into Dunglop's brain. He's broken through the skull with the bones sticking out of his fingers and is gorging himself on the juicy stuff inside, like a pig chowing down. Dunglop's still alive, shivering, eyelids flickering with terror and shock. But he doesn't scream. Just spasms.

Meths drops Rick and backs away from him. When Rick tries to crawl after him, Meths kicks him in the head and the boy collapses with a whine.

Seez is staring at the scratched Muslim, who wipes drops of blood from his chin, studies them and sighs. "A scratch might not be the same as a bite," he says.

"But we can't take that chance," Seez says quietly.

The Muslim sighs again. "I'll head for the front door. If I make it, and if I don't turn, I'll try to get help for the rest of you."

He darts through the doorway and is gone before Seez can say anything.

I glance at Pox and Dunglop one last time, my stomach turning, tears dripping down my cheeks. Then I curse hatefully and rush out after the others, leaving my dead and undead friends behind.