This time I heard a faint, guttural moaning that gradually increased in volume until it formed an unbroken wall of sound-a sound more heart-rending and terrifying than anything I'd ever heard before. I fought an urge to pull my sleeping bag up over my head and plug my fingers into my ears. A scream sliced through the unholy dirge.

I lurched out of the tent and tripped over Tommy, who was curled into a ball on the ground, hands clamped over his ears, crying repeatedly, "I can't stand it."

Jim was knelt at his side, saying, "Calm down."

The camp was a hive of activity. Everywhere figures were emerging from their tents, rifles gripped in their hands.

"They're attacking the fence," somebody shouted.

Figures wearing night-vision goggles streamed up ladders to lookout platforms. Within moments blue flashes were going off everywhere, the heavy boom of high-calibre rifles competing against the deafening rattle of automatic weapons.

I frantically rummaged through my kitbag for my Raptor S-63 night-scope. Bob was already busy attaching his night-scope to his rifle.

"Stay with Tommy," I shouted to Jim.

"You stay with him," he yelled back, s.n.a.t.c.hing up his AK-47 and sprinting for the nearest ladder.

I slung my rifle over my shoulder and hurried after him. Four figures were already knelt on the platform, squeezing off volley after volley. The noise was enough to knock the wind out of you.

"Mother of G.o.d," I breathed, squinting into my scope, "there must be a thousand of them."

The flesh-eaters were about 450 metres from the fence, advancing in a thronging ma.s.s. Fear gripped me-the same kind of primordial fear the Romans must have felt when they looked out of their encampment at the Barbarian Horde. Suddenly, I understood what the great hunters like Jesus Martinez must have known all their lives: this wasn't a game, it was war. Out there in the darkness was the enemy.

I shouldered my rifle, centred the cross-hairs and, tensing slightly in antic.i.p.ation of the recoil, squeezed the trigger. A zombie went down. I pulled the bolt back and fired again, shooting with mechanical efficiency, relaxing a little more with every bullet that slammed home.

Jim was in his element. Every so often, as he slapped another clip into his AK-47, I heard him laughing crazily.

Zombies were hewn down like corn beneath a pelting hail-storm. But still they came on, slowly, irresistibly. It was like we were trying to hold back a river with our hands. A hundred metres, fifty, ten. Then they were right beneath us, converging on the gate. The stink of decomposing flesh was overwhelming. I bent double, retching.

"Keep shooting you sonofab.i.t.c.h," screamed the man next to me.

As I swung my gun up, a series of explosions momentarily blinded me. Handfuls of grenades were being tossed into the seething ma.s.s below. Blood dampened our faces like spray from breaking waves.

Bob grabbed my arm. "Look what they're doing," he gasped.

My jaw went slack and, for a second, my brain refused to accept what I was seeing, but there was no denying it. The zombies were gathering their dead and stacking them against the gate to form a kind of crude siege-platform. They had no shortage of building material, either. The irony being that the faster we blew them back to h.e.l.l, the faster the heap grew. In no time at all it was almost as tall as the gate.

The situation was getting desperate. Dozens of zombies, driven into a howling frenzy by the scent of our flesh, were clawing their way to the heap's summit. We concentrated our fire on them, but for every one we picked off there were five more waiting to take its place.

It was only a matter of time before they broke through.

Jim wasn't laughing anymore.

A jet of flame streamed down, engulfing the mound of necrotic flesh. Several years ago dad managed to get his hands on an M-9A1 flamethrower that'd seen use by US troops during The Vietnam War. The first sentence of the training manual stated that: 'Flame has a powerful psychological effect in that humans instinctively withdraw from it, even when their morale is good.' Well flesh-eaters are no different in this respect and they retreated from the gate with howls of pain and fear. The plain was soon lit up like, well, like the biggest G.o.dd.a.m.n bonfire you could ever imagine, as those zombies that'd been doused with the lethally combustible mixture of gasoline and diesel staggered about setting alight anything they touched. It was a scene worse than any nightmare you ever dreamed.

We continued firing until the horde was out of range, although the accuracy of our shooting was reduced by a thick pall of smoke. Jim punched his AK-47 into the air, whooping. I was too exhausted to do anything besides crouch down, wiping sweat out of my eyes. I gratefully accepted a canteen off the man at my side and took a swallow of water.

"I ain't never seen nothing like that before," said the man-a craggy-faced old hand of about fifty, not exactly the type to get easily excited.

"If I hadn't seen it with my own eyes I wouldn't believe it," I said.

"We owe Hooch an apology," said Bob.

"Where are you going?" I asked as Jim started down the ladder.

"To check on Tommy."

A shout went up on the far side of the campground. "Here they come again."

You didn't need night-vision goggles anymore to see the amorphous ma.s.s of zombies shuffling towards us, the blaze at the gate illuminating their flesh-hungry faces.

"What the h.e.l.l," exclaimed Jim, returning to the platform. "There's twice as many of them as before."

"At least," said Bob.

"Where in Christ's name have they all come from?"

This question had already occurred to me. Zombies, as you know, are slow moving creatures. Even a stage one can't travel more than twenty miles in a twenty-four hour period. For the zombies to have reached the campground so soon after sundown, they must've been gathering somewhere within roughly a five mile radius of it. In which case, why hadn't they been detected by the spotters?

My train of thought was broken by a deafening barrage of gunfire. I joined in, concentrating every fibre of my being on the task at hand. Thousands of rounds a minute were being spent, the plain was as b.l.o.o.d.y as a butcher's slab, but it wasn't enough to stop the zombies. The first to reach the fence threw themselves on the ground, allowing others to clamber onto their backs. This process was repeated all along the fence. Spouts of flame swept over them. Fuel drums with grenades taped to them were flung onto their heads. The heat was so intense that even zombies that hadn't been sprayed with burning fuel started spontaneously combusting. The smoke made it impossible to pick out individual targets. We fired blindly, not knowing what else to do. It was getting difficult to breath. The man at my side suddenly dropped to his knees, clutching his chest and gasping.

"What's wrong, Harry?" asked one of his companions, flinging out an arm to stop him from keeling off the platform. "I think he's got a heart-attack," he said to me as Harry's face turned purple.

"There's someone coming up the ladder," said Bob.

We trained our guns on the ladder, waiting to see what would appear out of the smoke. A face so grimy with soot and sweat it took me a moment to recognise it emerged into view. "It's Cutshaw," I said. I swear I've never been gladder to see him than I was at that moment.

"What's happening?" asked Bob.

"There are zombies in the compound," said Cutshaw, po-faced as ever.

"Have you seen Tommy?" Jim asked.

Cutshaw shook his head. Jim started towards the ladder. I grabbed his arm. "Don't be a fool."

He tried to shake me off. "I can't leave him down there."

"He might have made it to another platform or even the bunker," said Bob (at the centre of every camp is a concrete bunker stocked with enough food and water to last fifty men a month).

"No way. You saw what sort of condition he was in."

"Whatever the case, there's nothing you can do for him," I said, one eye on Cutshaw who was drawing the ladder up onto the platform.

Jim glared at me. "Let go."

"No. You'll get yourself killed."

"I'm warning you-" Jim broke off mid-sentence as I released him. Seeing what Cutshaw had done, he yelled, "Put that f.u.c.king ladder back!"

Cutshaw faced him silently, immovable as a wall. Short of putting a bullet in the inscrutable b.a.s.t.a.r.d there was no way Jim was going to get his hands on the ladder. Jim's gaze swept resentfully over me and Bob as he turned and stalked to the opposite side of the platform. He emptied a full clip into the smoke, shooting from the hip, then yanked out the clip and hurled it away.

"I'm out of ammo," he said.

"Take Harry's rifle," said Harry's companion. "He won't be needing it anymore."

We all turned to look at Harry's contorted, dead face. He was about the same age dad had been at the time of his disappearance. Tears welled into my eyes. I lowered my head to hide them.

"We've got to deal with him," Cutshaw said.

"I'll do it," said Harry's companion whose name I later found out was Joe. He unholstered his pistol.

"Save your ammo." Cutshaw drew his hunting-knife and proffered it to Joe. I could've swung for the heartless swine.

Joe took the knife and held it against one of his friend's eyeb.a.l.l.s. "Sorry Harry," he murmured as he pushed the blade in. Then he used the knife's serrated edge to saw through the spinal-column at the base of the neck. As a final indignity, Cutshaw stripped off Harry's shirt. After tossing the decapitated corpse into the inferno, we cut the shirt into strips and tied them bandit-style around our faces to keep from breathing too much smoke.

Visibility was down to almost zero. "Don't shoot unless you're sure of your shot," said Cutshaw as we took up our firing positions again. He settled down by the ladder, rifle balanced across his lap.

Sporadic crackles of gunfire continued for a while, before a spooky calm settled over the camp. Once or twice I glimpsed shadowy forms at the base of the platform, but it was impossible to tell whether they were friends or foes.

"If it comes to it, you'd do the same for me, wouldn't you?" said Bob. "I don't want to end up like one of those things down there."

"You don't have to worry about that," I replied. "But it's not going to come to that."

"Yes it will, one day."

I glanced uneasily at Bob. What he'd said was obviously true, but it's a truth you learn not to think about too deeply. After all, what good can come from dwelling on something you've no control over? It's like that crazy king in that old English play said, 'That way lies madness.'

Day Seven.

Sunrise revealed a scene of devastation. It looked like a twister had ripped through the camp. Tents had been shredded, their contents strewn over the ground. Vehicles lay overturned. The gate had buckled from the heat and the sheer weight of bodies pressing against it. Flies swarmed around the corpses that littered the plain. There were no live flesh-eaters to be seen.

Cutshaw radioed for news of Tommy. Jim's head dropped when the last platform reported back that Tommy wasn't there. We lowered the ladder. Jim scuttled down it and rushed off in search of Tommy. We followed cautiously, handguns at the ready as we picked our way through the carnage.

"Over here," shouted Jim. He was squatted by the tattered remains of our tents. He held up a b.l.o.o.d.y rag. "It's Tommy's shirt," he said, voice choked. He looked at us pleadingly. "We've got to go after him."

Considering everything that'd happened, it was madness to even suggest such a thing. I was about to point this out, when Bob said, "Don't worry, Jim, we'll find him."

I looked at him in astonishment. "You can't be serious. It'd be suicide to go after Tommy."

"Have you forgotten what you said last night?"

"No, but this is different."

"How is it different?"

I spread my hands to indicate the encircling destruction.

"You do as you want, Mikey, but I'm going after Tommy." Bob held my gaze a moment, letting me know with his eyes that there was no point trying to change his mind.

"And just how the h.e.l.l are you gonna find him in all this mess?"

As if in answer to my question, Franz ran up to us wagging his tail. His fur was slightly singed, but otherwise he was fine. "This is crazy," I muttered as Jim held the b.l.o.o.d.y rag under Franz's nose. I turned to Cutshaw. "Tell them it's crazy."

"We'll need a serviceable hummer," he said, scanning the campsite. He approached a Humvee that lay on its side like a beached whale, followed by Bob and Jim.

"Has everyone but me lost their mind?" I said as I watched them struggling to tip the Humvee onto its wheels. Franz whined at me. "What do you reckon?" I asked him. He barked and ran towards the Humvee. With a resigned shake of my head, I followed him.

I braced myself against the bonnet. "Heave," I shouted, pushing with all my strength.

The Humvee's axles groaned as it tilted over. For an instant it tried to rock back onto us, but a figure charged into the gap between me and Bob and it dropped onto its wheels. Hooch grinned at me. "You looked like you needed some help. I heard about Tommy. I'm coming with you."

"Trust me, you should give this one a miss."

"You gotta be kidding, I wouldn't miss this for the world." Hooch sprinted off to salvage extra ammo from the wreckage of his tent.

There wasn't much visible damage to the Humvee. Cutshaw tried the ignition. The engine fired up first go. We piled in, drove over to the gate and contemplated the jumble of twisted metal and blackened corpses that blocked our path.

"That's gonna take hours to shift," Jim groaned.

"Not if we use this." Hooch took out a stick of dynamite.

"How old's that stuff?" I asked, eyeing it dubiously. Fresh dynamite's pretty insensitive to impact, friction and shock, but over time the nitro-glycerine can sweat out of it, forming into pure drops on the surface of the stick. When this happens even a small physical shock such as being dropped can cause it to explode.

"I only bought it last month."

We each took a bundle of sticks and blasting caps and a length of time (safety fuse). We weren't worried about doing further damage to the gate. The camp would have to be abandoned anyway until a team of engineers could be brought in to repair the fence.

I could feel the heat through the thick rubber soles of my hiking-boots as I clambered up the heap of corpses. I buried my bundle of dynamite near the top of the pile and threaded a long length of time into the bitter end of the blasting cap. I looked at the others and when each of them had given me the nod I lit the fuse. "Fire in the hole!" I shouted, hoping the heat wouldn't cause the cap to detonate before I'd retreated to a safe distance.

We ducked behind the Humvee, hands over our ears, mouths hanging open. An explosion rocked the Humvee. Body parts rained down around us. A severed head landed near my feet. By some incredible, awful coincidence it belonged to Harry. Its tongue protruded out of its mouth as if blowing a raspberry at me. I kicked the thing away.

Hooch whooped when he saw that a broad channel had been blasted down the middle of the mound. Only a few more bodies needed to be shifted to allow the Humvee to get through. The bodies were so badly burnt that their flesh crumbled like ancient parchment as we heaved them out of the way.

Cutshaw walked out of camp holding Franz on a lead. The rest of us followed in the Humvee. It didn't take Franz long to pick up Tommy's scent. We tracked it for a couple of miles over the plain to the south of camp before Franz lost the scent in a muddy creek. Jim's face twitched impatiently as Franz snuffled about. Franz rediscovered the scent on the far side of the creek a hundred or so metres to the north. Bob ploughed the Humvee through the mud.

"A large pack of zombies pa.s.sed this way a couple of hours ago," said Cutshaw.

"Was Tommy with them?" Jim asked.

"Yes. Most of the tracks lead south, but a small number, Tommy's included, lead northwest."

"What does that mean?" I asked.

"It may just mean the pack broke up." Cutshaw's voice was uncharacteristically hesitant. He stared at the tracks as if he was trying to solve a riddle.

"What is it?"

"There's something not ..." Cutshaw frowned. I swear, the inscrutable sonofab.i.t.c.h actually frowned.