'Yeah, but they don't know we're immune,' said Logan.

'Don't they?' she muttered darkly.

They were led to a door in the wall of one of the grey buildings, where the moustached guard pressed a button and spoke into a metal grille beside it. After a moment there was a buzz and the door clicked open. The moustached guard led them down a bare, narrow corridor, and from there through an interconnected series of functional low-ceilinged rooms. They reminded Logan of the claustrophobic Antarctic base in one of his favourite movies, The Thing.

Eventually they passed through another door and found themselves in a well-appointed laboratory, almost the entirety of one wall of which was dominated by stacks of cramped cages containing a variety of animals monkeys, wallabies, rats. Running round the other three walls was a waist-high counter cluttered with items of gleaming hi-tech equipment and several computer consoles, on each of whose screens were displayed graphs or diagrams or simply tables of fluctuating data.

Examining the readings on a piece of equipment that looked to Sam like some kind of over-elaborate cappuccino machine was a wiry man in his thirties with close-cropped sandy hair. Although he was wearing a white lab coat, he didn't match Sam's idea of a mad scientist at all. He'd been expecting someone older, with wild hair and maybe a pair of spectacles perched on his forehead. This guy, however, looked more like a mountaineer or a marathon runner. When they entered the room, he turned sharply to look at them, his eyes so startlingly pale and blue that for a moment he looked almost other-worldly. Then he smiled and bustled across, hand outstretched.

'Welcome! Welcome! I'm Dr West. How nice to have visitors. Way out here it happens so rarely.'

Of the three of them, Sam was the one who automatically put out his hand. The scientist's grip was surprisingly strong as he shook it.

'What's with all the animals?' Logan asked.

For a moment West's smile faltered and he glanced at the moustached security guard.

'Something wrong?' asked Purna.

'I was informed that you came here with Mowen? And that you had important information about a recent virus outbreak in the city?'

'That's pretty much it,' said Sam. 'So?'

West looked at Logan, his eyes piercing. 'So why ask me about the animals?'

Perplexed, Logan shrugged. 'Just askin', that's all. Hey, it's no biggie. You don't have to answer if you don't want to.'

West's face and body remained tense for a couple more seconds and then he relaxed, his shoulders slumping.

'Forgive me,' he said. 'I thought for a moment you had got in here under false pretences.'

'What false pretences would those be?' asked Purna.

West glanced at the caged animals almost guiltily. 'Well ... the nature of my research doesn't always meet with ... shall we say "universal approval"?'

'You're a vivisectionist?' said Purna coldly.

West winced. 'Please. That's such an emotive word.'

'What would you call it?'

'I'm a research scientist. I'm currently engaged on a programme of cosmetic testing.'

'On animals?' said Sam.

'Would you rather I used human beings?' snapped West.

Sam shrugged. Animal experimentation wasn't something he approved of exactly, but neither did he feel strongly enough about the subject to engage the doctor in a moral debate. 'Hey, you gotta do what you gotta do,' he mumbled. 'Stuff's gotta be tested somehow, I guess.'

'Exactly,' said West. 'Though try telling that to the animal activists.' Perhaps realizing he was getting a little too emotional, he made an obvious effort to relax, and eventually managed a tight, somewhat twisted smile. 'That's why we're right out here in the ... ah ... boondocks, as it were.'

'Is that the only reason?' asked Purna.

West's expression was now one of polite puzzlement. 'What do you mean?'

'This virus we came to talk to you about,' said Purna. 'There are people out there who claim you're responsible for it.'

West laughed. 'Do they now? Well, that's a new one, I must say.'

'It was Mowen himself who claimed it originated from here. He told us it was common knowledge among the local people.'

'The mad scientist lurking in his jungle hideaway, unleashing all manner of monstrosities on the world?' West said, and laughed again, longer and harder this time. 'I'm afraid the local people are a superstitious lot. They don't trust anything they don't understand.'

'You know something about the virus, though, don't you?' pressed Purna, her tone remaining just this side of accusatory. 'Otherwise why would you have been so willing to see us?'

'Perhaps it's just that I crave company. It does get terribly lonely out here, you know.'

Purna smiled tightly. 'Do you honestly think we're that stupid, Dr West?'

Another disarming laugh. 'Of course not. I was curious, that's all. Why would the three of you come all the way out here to talk about a virus endemic to the local tribesmen? It struck me as odd that you would even know about such a thing. And then, of course, there is your appearance.' He gestured towards them. 'Raoul informed me that you looked as though you had just emerged from a pitched battle. And he was right.'

Purna stared at him hard and long. 'You really don't know what's been happening?'

'Communication networks are unreliable out here at the best of times. These past twenty-four hours they have been non-existent.'

'Oh, man, are you in for a shock,' said Logan.

West frowned. 'Why? What has happened?'

Sam looked at his companions and blew out a long weary breath. 'Who's gonna start?'

They spent the next thirty minutes filling West in on the grim events of the past twenty-four hours. The scientist reacted with horror and shock, but he didn't seem quite as surprised as they might have expected. When Purna questioned him on this, he said, 'I confess, I was aware of the virus, and was concerned that it would eventually spread into the wider population. But I must say, what you've just described is way beyond any worst-case scenario I might have envisaged. When I first came here six months ago, a delegation from the Kuruni that's the local tribe asked me to examine a man who was suffering from the virus. From what I could gather, the Kuruni have been afflicted with it for generations, and have come almost to accept it. It's a cumulative illness that can strike at any time during a tribesman's or woman's adult life, and it eventually leads to dementia and death. However, what the Kuruni seemed to be telling me was that recently the nature of the virus had changed, and that somehow the villagers who were dying from it were then returning from the dead as ... I don't know ... demons? Evil spirits? To be honest, I took a great deal of what they were saying with a pinch of salt; I simply assumed they were hysterically interpreting the symptoms of extreme dementia as some kind of ... supernatural mumbo jumbo. Anyway, I examined the man's blood and discovered that his symptoms were reminiscent of Kuru, a prion disease that affects the brain. To put it in its most basic terms, it's like a human version of mad cow disease, and it is believed to be caused by cannibalism.'

'Cannibalism?' repeated Logan.

West nodded. 'The Kuruni are cannibals, have been for generations.' He hesitated, then said, 'Although I managed to separate and identify the virus, what particularly disturbed me about it was that it was not only highly contagious, but it was also unstable, constantly mutating. However, the puzzling thing was why given that the virus was so contagious the entire Kuruni population had not long ago been wiped out by it.'

'They had a natural immunity, you mean?' asked Purna.

'Not all of them, but a significant proportion of them, yes.'

'Like us,' said Sam.

'So what's to stop you taking a sample of our blood and whipping up a quick vaccine here and now?' asked Logan.

West smiled. 'Maybe I could if I had a stable form of the virus. The thing is, though, your immunity may be simply an anomaly, something that works for you, but doesn't necessarily work for everybody.'

'So what would you need to maximize your chances of creating an effective vaccine?' asked Purna.

West said, 'Ideally a blood sample from an immune Kuruni villager, in which the genetic signifier would be dominant and therefore unmistakeable, plus a sample of the stable form of the virus.'

'A stable form?' said Logan. 'What does that mean?'

'It means one that hasn't reached the stage where it's constantly mutating.'

'From someone who died a while ago, you mean?' said Purna.

West nodded.

'So when you say "a while ago",' said Sam, 'how long ago we talking here exactly?'

West shrugged. 'A year. Maybe two to be certain.'

Sam looked nonplussed. 'So you need a blood sample from an immune villager, plus a blood sample from some dude who died of the virus two years ago?'

'The stable form of the virus doesn't have to be a blood sample,' said West. 'Any DNA sample would do.'

'Oh, why didn't you say so?' said Sam with heavy irony. 'That's easy. All you have to do is dig some dude up and chop off his finger or somethin'.'

'So if we can get you these things,' said Purna, 'you'd be willing to develop a vaccine?'

'I'd be willing to try, of course,' replied West, 'but there would be no guarantee I'd be successful.'

'But how long would it take?' Purna asked. 'Doesn't it usually involve months of lab work to come up with these things?'

'It can do,' West replied, wafting a hand vaguely, 'but it all depends on the nature of the infection. And I have already done some groundwork, remember. We may strike lucky if you can bring me what I need.'

'Hey, wait a minute,' said Sam. 'How come we're doing this? The doctor here's friendly with these guys.'

West shook his head. 'I'm not really, you know. I may have befriended a few of the Kuruni people, but the majority are hostile. Plus I'm not immune to the virus like you are. I was extremely fortunate not to contract it from the infected Kuruni man I examined. Luckily for me, the virus was not in its later, most contagious phase at the time, and my contact with the patient was minimal, not to mention conducted under the strictest of laboratory conditions. It was only afterwards, when I realized what I had been dealing with, that it struck me what a lucky escape I'd had.'

'So let me get this straight,' said Sam to Purna. 'You're wanting us to go deeper into the jungle to look for a village of mean motherfucking cannibals, so that we can ask them for some blood and for permission to not only dig up their dead relatives, but to chop little bits off 'em.'

'Put like that, you make it sound so bad,' said Logan.

Purna smiled grimly. 'What's the problem? We've got guns, haven't we?'

'Well, whoop-di-do,' said Sam.

Chapter 15.

HEART OF DARKNESS.

'WE STOP HERE. Now you walk.'

West had instructed Raoul, the moustached guard, to lend them one of four open-top jeeps parked in a smaller clearing just north of the research centre. Mowen had told Purna, Sam and Logan that the route to the Kuruni village had been formed over the centuries by the passage of feet, not vehicles, and that it would therefore be narrow and uneven, but passable. When Purna had asked for directions to the village, Mowen had surprised her by saying there were many paths, and that they would quickly get lost without him.

'But it's too dangerous for you to come with us,' Purna said. 'There's sickness in the village.'

Mowen grinned and patted his chest. 'I not get sick,' he told her.

At first she wondered whether he was immune like the rest of them, but when, after a stopstart journey during which they had had to get out of the jeep a dozen times to hack a path through the dense vegetation, he cut the engine and instructed them to walk, she realized he meant he had no intention of getting too close to the action.

'How far is it?' she asked.

He raised his hands as if the distance was negligible. 'Less than one hour.'

'And you'll be here when we get back?'

He nodded. 'Yes. I wait.'

Purna hesitated, and Sam knew she was debating whether to issue a warning about what would happen to him if he let them down. However, in the end she simply said, 'OK. Thanks, Mowen. See you later.'

They began to walk, flies and mosquitoes buzzing around them, their journey accompanied by the ever-present chorus of birds and insects. Although Sam was pretty sure they'd hear if one of the infected came crashing towards them through the undergrowth, he wondered how aware he, Purna and Logan would be if the regular cannibals started to stalk them. This was their natural habitat, after all, and for all Purna's training and athleticism the three of them were little more than prey out here. Their guns might give them a certain amount of reassurance and authority, but Sam couldn't help but think it was a false comfort. He'd seen those old Tarzan movies as a kid and knew how easy it would really be to bring them all down. A bunch of curare-tipped blowpipe darts in the backs of their necks, and that would be it.

Something else that concerned him was the time factor. With the sun still high overhead, it was easy to forget that it was now late afternoon. Sooner rather than later, therefore, it would start to get dark. If it took an hour to walk to the Kuruni village and an hour to get back, it would be early evening before they rejoined Mowen at the jeep, by which time the sun would be sinking rapidly towards the horizon.

Although Sam really didn't like the thought of being stuck out in the jungle at night, he kept his fears to himself. There was no point expressing them until the possibility became a reality. He hoped everything would work out OK, in which case they could bed down at the research centre tonight, head back to Mowen's village with the vaccine in the morning, then get the trader to take them all out to the prison. With any luck, by lunchtime tomorrow they would be sitting in a chopper and heading away from this fucked-up place.

The first indication they were nearing the village was when they heard the faint jabber of raised voices beyond the screen of vegetation ahead. Purna glanced back, gesturing at Sam and Logan to move quietly, then crept forward, her body bent in a crouch.

For a minute or more the sounds rose and fell, as if carried by the faint warm breeze that intermittently rustled the leaves of the plants around them. Then they began to consolidate, to acquire substance. Now, although none of them could understand the words being spoken, Purna, Sam and Logan could tell the voices were full of fear and urgency, and that underpinning them were the familiar heart-sinking snarls and moans of the infected.

When the quality of the light lancing through the gaps between the fleshy overlap of leaves became more piercing and less green, they knew they were reaching the edge of the jungle. Purna glanced back once again, perhaps simply to reassure herself her companions were still closeby, then she bent down and carefully parted the leaves with both hands so they could all peer through them.

More by luck than judgement, the gap she had made framed a perfect tableau of what was happening in the village. At the end of a long, dusty street lined with conical hive-like huts of mud and grass, was a cluster of mature trees, which marked the boundary between the far side of the village and the continuation of the jungle. Perched in the branches of the trees were at least a dozen people, the shadows cast by the fleshy-leaved branches reducing them to little more than bobbing-headed silhouettes. Their voices, calling to each other, could clearly be heard. They were quarrelling voices, full of anxiety and anger; voices bordering on, and occasionally spilling over into, panic.

The reason for their distress was obvious. Gathered at the base of the trees, reaching up to scrabble and claw at the trunks, or simply at the air, were dozens of the infected. They were clambering over one another in an effort to get closer to their potential prey, though fortunately they seemed unable to coordinate their thoughts enough to climb the trees themselves. However, without help it would surely only be a matter of time before what now appeared to be the minority of Kuruni people still unaffected by the virus succumbed to thirst or hunger or simple fatigue and fell into the clutches of the ravenous hordes below. From the evidence it appeared that events here had suddenly and shockingly come to a head, and that after years, perhaps centuries, of living with the virus, the balance of the scales had tipped and the dead perhaps through sheer weight of numbers had instigated some kind of bloody, albeit mindless, coup.

Aside from the few villagers who had had the luck and foresight to head for the only safe direction straight up, into the trees it was obvious that the Kuruni tribe had been decimated by the attack. Between the edge of the jungle where Purna, Sam and Logan were crouching, and the trees providing temporary sanctuary for the survivors at the far end, was a scene that resembled the aftermath of an explosion. Dozens of mutilated bodies were lying in pools of blood along the dusty street, many of them missing limbs, or with their flesh stripped down to the bone or their stomachs ripped open and their entrails exposed to view. Most were permanently and mercifully dead, their remains crusted with fat and feasting flies, though there were a few that had been resurrected by the virus and were now wriggling pitifully in the dirt, trying desperately to re-animate bodies that were damaged beyond repair.

Sam swallowed, his mouth dry, his mind reeling at the sight of this fresh atrocity.

'Fuck me,' Logan whispered. 'Guess we're a little late, huh?'

'We still have to help those people,' whispered Purna. 'We can't just leave them up there.'