Although she was certain she had done it right, Xian Mei knew this was no time to argue. She stepped back and allowed Purna access to the keypad. A few feet away Sam pulled the trigger of his gun and out of the corner of her eye Xian Mei saw the naked man's head become a crimson spray. As the zombie pitched backwards down the steps, Purna punched in the four-number code. It gave Xian Mei no satisfaction to see the light remain stubbornly red.

'Shit,' Purna muttered and stepped away from the door. She turned to assess the situation, raising the shotgun.

Two zombies were coming up the steps towards them, an old man and a teenage girl. The old man was shambling, dragging his left leg behind him; the girl was running, almost scampering, lips drawn back in a snarl, the metal braces on her teeth clogged with blackening meat. Further away, other zombies seemed to be receiving the signal that there was fresh meat to be had here, and were turning round, sniffing the air, homing in.

Clinically, Purna took the girl out, the shotgun blast hitting her right in the centre of her face, reducing her features to pulp.

A few steps below her, Sam glanced round. 'What's going on?'

'Those bastards must have changed the entry code,' Purna said.

'How they do that?'

'They've got Dani, remember?'

'Shit!'

'We'd better get back to the van and rethink this,' Purna said.

'What about the food?' asked Xian Mei.

'Leave it.'

They were halfway back down the steps when a chunk of stone exploded less than a metre away from Sam's foot. He stared at it uncomprehendingly for a split-second and then something whacked into the pavement below, causing a mini-eruption of stone chips.

'Get down!' Purna yelled.

Sam ducked instinctively. 'What the fuck?'

'They're firing at us,' she said, dropping to a crouch, spinning round and pulling the trigger of the shotgun all in the same movement. As the shotgun blast hit the building and Purna hastily reloaded, Sam was aware of Xian Mei, bent almost double, leaping down the steps to his left.

'Go,' Purna said. 'I'll cover you.'

Knowing as Xian Mei had done before him that there was no debating the matter, he ran down the steps, catching up with Xian Mei at the bottom just as she straightened up and fired her flare pistol at a zombie that was still fifteen metres away, but approaching rapidly enough that it would have reached them before they had chance to open the van doors and scramble inside.

The front of the zombie's shirt burst into flame and a sheet of fire rose up and engulfed its head. It began to stagger around, arms waving like a kid playing blind man's bluff, as its face browned and sizzled like barbecue meat.

The other zombies were still far enough away for them not to be an immediate problem. Keeping an eye on the burning zombie, Sam pulled open the passenger door of the van and shouted, 'Get in.'

Throwing her machete into the foot well, Xian Mei dived across the front seat and scrambled upright. Sam climbed in after her, then immediately turned, pointing his gun up at the police station. The oldest of the three guys was at one of the upstairs windows, albeit trying to keep out of sight, the barrel of his hunting rifle resting on the sill. Purna was crouched down, trying to use the steps as cover. Although the nearest of the infected was still twenty metres away from her, they were closing in from all sides.

'Come on, Purna!' Sam shouted, and fired a bullet towards the upper window of the police station to demonstrate that he was now in a position to cover her.

She needed no second bidding. Breaking cover, she ran across to the van, Sam scooting along the seat to give her room to dive in and slam the door shut behind her.

As she was doing it, the door of the police station opened and the tattooed guy ran out, keeping low, and quickly dragged the discarded boxes of food and the pack of water bottles inside. Seeing him, Purna wound down the driver's window a few inches and stuck the barrel of the shotgun out, but before she could fire he was back inside the building and had closed the door behind him.

'Bastards,' she muttered.

'What-' Xian Mei began. But before she could complete her question the gloating voice of the scrawny man called out from an upstairs window.

'Hey, thanks for the food, guys. We're real sorry that we're no longer in a position to offer you anything in return. Oh, you can have your boy back, though. We've finished with him.' There was movement at the window and the dead or unconscious body of Dani was dropped out. He hit the ground head-first, his limbs splaying in all directions. The men in the building cackled and whooped as though this was the funniest thing they had ever seen.

'Think we'll keep the girl, though,' the scrawny man said after a moment. 'We need us a little recreation.' He sniggered again, then shouted, 'You folks take care now. Make sure the zombies don't get you.'

The window slammed shut and their sight of the building was blotted out by a middle-aged man with thinning hair and a punctured eyeball, who lurched into view and snarled in at them through the driver's side window. Without hesitation, Purna pulled the trigger of the shotgun and his head exploded in a gory confusion of blood, bone, flesh and brain. Yanking the gun back into the van, Purna wound up the window and turned on the engine. With zombies moving in rapidly, she drove away.

Chapter 11.

GOING UNDERGROUND.

'I THINK I might know a way.'

Purna and Sam looked at Xian Mei. Once again they had parked in the car park at the back of the supermarket, having needed to find somewhere quiet where they could talk over what to do. In the back of his mind Sam had been worried that Purna might take the hard line, dismissing Jin as a casualty of war and proclaiming that, though the situation was regrettable, it was not worth risking all their lives simply to rescue a girl who was not even prepared to handle a weapon.

However, he had underestimated her. Unless she had some ulterior motive (the stash of weapons in the armoury maybe?), she wasn't entirely the hard-nosed pragmatist he had taken her for. True, she had told them earlier that she had joined the police force because she wanted to help people who couldn't help themselves, but Sam had assumed her noble aspirations had waned in the wake of her dismissal from the force and the general disillusionment with life that she had suffered since. It was good, therefore, to see her so outraged, so impassioned, so concerned for Jin's fate.

'We've got to get her out of there,' she had said. 'If those fucking animals harm her I'll never forgive myself.'

When Xian Mei said she thought she might know a way to get into the police station, Purna leaned forward eagerly. 'How?'

'In the hotel where I worked,' Xian Mei said, 'there was an old sewer outlet in the basement laundry. Someone told me that the tunnels ran right under the main street, and that at one time you could gain access to every building from below if you wanted to.'

'At one time?' repeated Purna. 'You mean you can't any more?'

Xian Mei shrugged. 'I don't know. I'm not an expert. But this is the old sewer system we're talking about. I guess whoever's in charge of these things eventually decided it was unsanitary to have sewage constantly flowing directly underneath people's homes and either diverted the flow or built an entirely new system. It could be that the old tunnels are impassable now. They could have been blocked up or the access to certain buildings might have been sealed. There have been a lot of renovations to some of the buildings over the years. Extensions, new walls and floors, maybe even new foundations in some cases ...'

'It's worth a try, though,' Purna said. 'The vulnerable parts of buildings are always either above or below. And unless you can climb walls like Spiderman or you've got access to a helicopter ...'

She let her words hang in the air. Sam nodded. 'Let's do it.'

'We might be able to gain access from the supermarket,' Xian Mei said. 'We should look for the lowest point.'

It took them less than five minutes to find what they were looking for. The warehouse floor was concrete but inside the supermarket itself they found a fire exit tucked away behind the frozen foods section. Beyond this was a short corridor leading to a door that led outside and a set of stone steps to a basement area, which had not been used in a long time, except as a dumping ground for some old and rusting shelf fixtures. A couple of minutes' searching resulted in the discovery of a circular iron manhole cover in the corner of the stone floor, crusted with moss and gunge.

Sam tried to lift it, but it was fixed solid. 'We need something to lever it up,' he said.

Xian Mei walked over to the shelf fixtures and dragged out a metre-long V-shaped metal bracket. 'What about this?'

'Perfect,' said Sam. 'There any more of those in there?'

Xian Mei found another two and they set to work, first scraping away as much of the slime and moss as they could from around the rim of the manhole cover, then ramming the metal edges of the brackets into the thin gap between cover and floor and applying their collective weight to the other ends.

After ten seconds, there was a creaking groan and the manhole cover started to rise. As the gap widened, they rammed their brackets in further to gain more purchase, and suddenly the cover tilted up and over like a hinged lid, clanging to the ground with such force that Xian Mei had to jump out of the way to prevent her foot getting crushed.

They all recoiled from the fetid smell that rolled up from the hole in the floor.

'Jeez!' Sam exclaimed, clamping a hand over his nose and mouth. 'You think any of those things are down there?'

'Don't see how they'd get down there, or why they'd want to,' said Purna. 'They only tend to go where the fresh meat is.'

They peered into the hole, but it was pitch-black. 'Anyone got a flashlight?' asked Sam.

Purna pulled a face and shook her head. 'They'll probably have them in the store upstairs. Damn, I should have thought of that.'

'Don't beat yourself up about it,' Sam said. 'You can't think of everything. I'll go get one. Be right back.'

'Don't say that,' said Purna.

Sam raised his eyebrows. 'Why not?'

'Because that's what they always say in horror movies just before ...' She made a sharp crrrk sound and drew a finger swiftly across her throat.

Sam grinned and disappeared. Two minutes later he was back, preceded by the circular shining disc of a heavy-duty flashlight.

'Quiet as the grave up there,' he said, and again flashed his teeth in a grin. 'Guess I shouldn't say that either, huh?'

He shone the flashlight into the hole, to reveal a circular stone tube like the inside of a well, the walls covered in green-black slime. Despite the light it was too dark for them to see all the way to the bottom. Iron rungs were set into the wall, and Sam dropped to his knees, reached down and gripped the first one to test how strong it was.

'Seems OK,' he said.

He went first, stopping every now and then to shine the beam of the flashlight down into the darkness. It was awkward descending with their weapons, especially as the rungs were slippery with slime, but they managed somehow. The deeper they went, the colder it became, the air heavy with the stench of rotting vegetation. Eventually Purna said, 'I hear water.'

Her voice echoed hollowly off the walls. When the echoes had died away, they all heard the sound of rushing water below. They continued their descent, the sound getting louder, until at last Sam called, 'We're nearly there.'

'What can you see?' Purna asked.

'Moving water. Not much else. Wait, there's a kind of ridge at the side, like a raised path. Looks kind of narrow.'

'But passable?'

'Yeah, I think so.'

A minute later they were standing at the bottom of the ladder, catching their breath. They were standing in a square stone tunnel on a slippery, wet, narrow sidewalk, beside which oil-black water flowed like a river, glittering and rippling under the flashlight beam.

The tunnel stretched straight and unbroken in both directions. Pointing against the flow, Sam said, 'I guess we go this way?'

Purna nodded and they started to walk, their feet splatting in puddles of water.

'It don't smell like sewage,' said Sam.

'I don't think it is,' said Purna, 'but I wouldn't wash your face in it.'

'I'm not sure it's supposed to be flooded like this,' said Xian Mei. 'It could be because of rising sea levels. There are lots of internal waterways and swamplands on Banoi and they all link to the ocean. These tunnels may have just taken some of that extra water on board.'

'You mean this is sea water?' said Sam.

Xian Mei shrugged. 'Well, that's my theory.'

'Damn,' Sam said. 'Shoulda brought my fishing rod.'

Walking along in single file, they lapsed into silence, the flashlight beam slithering and jerking ahead of them. Passing another of the vertical shafts which linked the disused sewer tunnels to the surface, Xian Mei said, 'There are five buildings between the supermarket and the police station, so the sixth shaft we come to should be the one we want.'

They walked on, passing another shaft and then another. Suddenly Sam stopped.

'What's wrong?' Purna asked.

'Thought I saw something in the water.'

'Like what?'

'I dunno. Something surfaced, then went back under with a splash.'

'A fish?'

'Maybe. Or perhaps just a log or something.'

'I wouldn't worry,' said Purna. 'I don't think the infected can swim.'

Sam nodded, and was about to set off again when something erupted from the water a few metres ahead of them. In the flashlight beam he saw a pair of wide-open jaws edged with pointed teeth, and an enormous grey-pink gullet.

Purna had shoved Sam aside and fired both shotgun barrels into the elongated mouth before he had registered it was a crocodile. The bullets tore into it, shredding its tongue and the underside of its upper jaw, turning the inside of its pink mouth a sudden and startling red.

The massive creature at least five metres long from snout to tail twisted in mid-air, like a vast fish caught in a net, so close to them that Sam could have reached out and touched its ridged prehistoric hide. Then it crashed back down into the water, sending up a wave that surged over the narrow sidewalk and drenched them from head to toe. Sam watched as the creature submerged, slipping beneath the now-churning black water like an enemy submarine. He was both awestruck and more terrified than he had ever been in his life. For a few seconds he could neither move nor speak.

Then Purna shoved him in the back. 'Get going,' she said.

Sam forced his legs into action, stumbling ahead of her.

'Is it dead? Did you kill it?' Xian Mei panted from the rear of the group.

'No idea,' replied Purna. 'And I'm not hanging around to find out.'

By the time they reached the sixth shaft they were still shaking with shock and a raw, primal terror that the creature might attack again. Even Purna was finding it difficult to hold the shotgun steady as she turned briefly to scan the black water behind them.

'You go first,' Xian Mei said to Sam. 'I don't think either Purna or I will be able to push up a manhole cover from underneath.'