Billy kept close to Lightning as they crept through the badgers’ sett. It led deep beneath the courtyards of the sprawling fortress and smelled musty, like the elephant house at a zoo. In places it became so low he had to crawl on all fours, shuffling past straw-filled chambers where the badgers slept. Billy was sure two beady eyes stared back at him from amongst the bedding.

The rest of the Runners followed on behind, bickering excitedly until Lightning had to tell them to be quiet once more. Then, pushing past a tangle of roots protruding from the earth, the tunnel began to climb and Billy emerged from a hole in a ramshackle garden in the town.

He peeped over the garden wall. The street was full of creeping shadows cast by a waxy moon, but he recognized it as Shipton Road.

‘OK, I know where we are. Follow me,’ he called in a hushed whisper, and led the motley crew through the empty town, swallowing his fear as he peered nervously around corners before dashing across deserted streets. He knew every building, and even though they looked distorted and threatening in the dark, he somehow half expected to see someone he knew walk casually around a corner. Here was the coffee shop his mum always visited when they went shopping in town; there the bargain store, usually thronged with people; opposite was the spot where the homeless man sold magazines, but it was empty apart from the little square of cardboard where his scruffy dog usually sat.

Billy strained his ears for the sound of a car purring along a nearby road, or for the chimes of the town clock. But the clock was stopped and the streets as empty as a ghost town. Not an owl hooted, not a tomcat yowled. There were no sounds of footsteps, of voices calling out, or police cars wailing. It was so quiet, Billy was sure he could hear his own heart beating. Even though the Runners were with him, he felt scared and vulnerable, and it made him want to yell at the top of his voice: ‘Is anybody there?’

Finally, they arrived at his house on Merlin Place.

‘This is it!’ he whispered to the excited Runners.

The driveway was crisscrossed by shadows, and the gravel crunched under their feet as they crept towards Billy’s house. The bushes on either side rustled in the night breeze.

Billy ducked into the porch, lifted the flap of the letter box and peered inside. His house was still deserted, and it made him feel like a stranger, as if he didn’t belong there. Hoicking up the skirt of his robe, he dug down into his jeans pocket, found his key and inserted it into the lock. It wouldn’t turn.

‘There, you see? It’s locked solid,’ he whispered. ‘Back door’s the same too.’

‘It must be deadlocked, but that’s no problem. I can easily get around that,’ said Ace, taking a rolled-up pouch from his pocket. He opened it and chose two long tools from a row of lock picks.

‘Cool!’ said Billy.

‘Right, I need complete silence,’ said Ace, cracking his knuckles like a safebreaker and inserting the picks into the lock. ‘Mmm, this is a tricky one,’ he added, his ear resting against the door.

Billy watched impatiently as the boy twiddled and turned the picks. It was taking ages, and he became more and more impatient as the seconds ticked by. Ace grimaced and took a finer tool from his pouch. Eventually, with a grunt of frustration, he gave up.

‘It’s no good,’ he said. ‘I can’t do it!’

‘You’re joking!’ cried Billy. He was devastated. The thought he might not be able to get home was almost too much to bear, and all his frustrations and fears came rushing to the surface.

‘You weren’t trying hard enough! Let me have a go,’ he yelled, but without warning Ace spun him round and clamped a hand firmly over his mouth.

‘Mmm, mmm, mmm!’ protested Billy.

‘Quiet!’ whispered Ace. ‘Crawlers!’

To his horror Billy saw three figures slink into his driveway. They were the same as the nightmare creature that had visited his bedroom – little wild-haired men with jagged teeth as sharp as a shark’s, and just the sight of them made his stomach turn.

The crawlers momentarily disappeared behind some shrubs, and Billy found himself being dragged out of the porch and behind the thick foliage of a nearby hedge at the side of the house.

‘Quick, everyone, behind here!’ whispered Lightning.

The creatures reappeared and crept towards them, hissing like leaking boilers. Billy’s chest tightened with panic as the little crawling men climbed the steps into the porch and began sniffing about, their noses gurgling with mucus. They were just a couple of metres away and he knew it was only a matter of seconds before they were discovered.

This mission had been Billy’s idea, and now everyone was in danger. It was up to him to do something about it. Silently, and with shaking hands, he picked up a large stone from the flower bed and flung it towards the back garden.

The crawlers jumped as the stone clattered through the undergrowth beyond, and scurried over to the tall iron gate that led into the back. As they peered eagerly through the bars they were only a couple of steps away, and Billy held his breath as he carefully picked up another stone and threw it high over the gate. This time it hit his mum’s greenhouse, and there was a crash of breaking glass. With excited yelps the crawlers flung the gate open and raced through it.

‘Run for it,’ Billy whispered, his voice hoarse with fear, and as the gang hurried off down the drive he darted up to the gate, pushed it shut and turned its rusty key. He breathed a sigh of relief – but a crawler’s thin pale arm snaked back between the bars. It grabbed Billy’s wrist and yanked him towards the gate, and his head hit it with a resounding clang.

He slumped to the ground, dazed. Another crawler joined in, pulling Billy so close to the gate his face was tight against the bars – only centimetres away from the crawler’s snarling, spitting mouth!

‘Get off!’ Billy yelled, but the crawler opened its jaws to reveal a row of sharp, triangular teeth. Then, giggling like a crazed hyena, it bit down on his arm.

‘Aargh!’

Suddenly a heavy branch was driven between the bars and hit the crawler hard on the forehead. It let go with a scream, and scurried off into the garden, holding a bleeding wound. Billy looked up to see Lightning standing above him, wielding the branch like a battering ram.

Whack! She drove it into the stomach of the second crawler, and it gasped and leaped back, retching noisily. But the third crawler jumped at the gate and started to climb as effortlessly as a monkey. In a second it was atop the gate and grinning down at Billy and Lightning.

‘Watch out,’ yelled a high-pitched voice, and Billy saw the short round figure of Compass running towards them. As she passed a moss-covered birdbath, she lifted its bowl free and hurled the contents at the crawler. The water hit the creature full in the face. It lifted its hands to its eyes and started to yowl, dropping back into the garden and writhing on the ground.

‘Run!’ yelled Billy, scrambling to his feet, and they ran down the drive and out on the street to join the other Runners. The whole gang took to their heels and pelted down the road, turning into side alleys and back streets, and didn’t stop until they were convinced the crawlers hadn’t followed them.

‘How on earth did you know they hated water?’ Billy asked Compass. He was still shaking from a surge of adrenaline.

‘I didn’t,’ said Compass. ‘I meant to hit it with the birdbath!’

‘It did the trick, anyway,’ grinned Lightning. ‘We’ll have to remember that for the future. How’s your arm, Billy?’

Billy pulled the sleeve of his tunic up and looked at his forearm. There was a row of indentations in his flesh from the crawler’s teeth, but the fabric of the tunic was thick and his skin hadn’t been broken.

‘I’ll live. Look, I’m really sorry I got your hopes up – and put your lives in danger too,’ he said.

‘Don’t worry, we should have told you there’d be crawlers about. It’s their job to patrol the streets,’ said Lightning, and gave him a reassuring smile. ‘You sure you’re OK?’

Billy nodded.

‘Then let’s do some scavenging, whilst we’re here. Come on.’

Billy followed her down a narrow street that led to the little row of shops near the park. He knew this part of town really well, but when the gang squeezed between the bars of the park gates, he stopped in amazement. It was almost unrecognizable. Gone were the swings and slides, the football pitch and the skate park he knew so well. Now, every square metre was given over to growing vegetables.

Billy hunkered down behind a park bench with the others.

‘Has everyone got their scavenging bags with them?’ whispered Lightning.

The others nodded, pulling canvas sacks from the deep pockets in their gowns.

‘I haven’t,’ said Billy.

‘Never mind. You stay here and keep a lookout. The crawlers are bound to be looking for us now. If you see any, just whistle.’

‘Er, yeah, OK,’ he said, a little uncertainly. He didn’t want to be left alone in the windswept darkness, but he wasn’t going to show he was afraid.

They were gone in a flash, and Billy crouched behind the bench and surveyed the bewildering scene. Before him the vegetable plots disappeared into the dusky distance; to his right was a row of familiar houses from his town; but over to the left the black fortress rose high into the dark sky. A new tower was being built, and hundreds of night-children were moving over it like worker ants, hauling up blocks of stone on pulleys and swinging them into place. Billy was glad he wasn’t one of them.

Minutes ticked by, and he began to get edgy. He could hear the rustling of wind through the crops and the snorting of unseen night creatures, but he couldn’t see his friends anywhere. Suddenly, half a dozen crawlers appeared in the distance. They began to creep up and down the paths between the vegetable beds, peering eagerly amongst the foliage.

‘Uh-oh!’ Billy whispered to himself. He puckered his lips, ready to whistle a warning, but they were so dry he only managed to blow a raspberry. He caught a glimpse of the Runners in the moonlight, halfway across the park – tiny figures dashing along the rows of beans. He wet his lips and tried again, emitting a warbling trill. The Runners dropped to the ground as if they’d been shot and Billy watched nervously as the crawlers moved closer and closer to where they had been.

He heard a distant hiss as a crawler waded in amongst the vegetables, frantically sweeping their leaves aside, and then stooping to grab something.

‘They’ve been caught!’ gasped Billy.

Then a hand tapped him on the shoulder and he nearly jumped out of his skin. He turned to see the grinning face of Lightning. The Runners had returned as silently as cat burglars, their home-made bags bulging with pilfered vegetables.

Billy gave a huge sigh of relief, and without another word they set off for their lair deep below the fortress.