He finally brought them to a halt, and they huddled down in the lee of a crumbling wall. In low whispers they debated what to do next.

  "If we start running it won't matter if we come across a patrol. We can easily shake them off in this," Cal suggested quietly, his eyes darting left and right under the moisture-spotted lenses of his gas mask. "We just keep running."

  "Yeah, right," Will replied. "So you really think you could outrun one of those dogs? I'd like to see that."

  Cal humphed angrily in response.

  Will went on. "Look, we don't have a clue where we are, and if we have to make a run for it, we'll probably hit a dead end or something…"

  'But once we're in the Labyrinth, they'll never catch us," Cal insisted.

  "Fine, but we've got to get there first, and for all we know it's still a long way off." Will couldn't believe his brother's absurd suggestion. It dawned on him that a couple of months ago he might have been the one advocating the crazy dash through the streets of the city. Somehow, he'd changed. Now he was the sober one, and Cal was the impulsive, headstrong youngster, chock-full of madcap confidence and willing to risk all.

  The furious whispered exchange continued, growing more and more heated until Cal finally relented. It was to be the softly-softly approach; they would inch their way to the far edge of the city, keeping the sounds of their footsteps to a minimum and melting into the fog if anyone, or anything, came close.

  As they stepped over hunks of rubble, Bartleby's head was jerking in all directions, scenting the air and the ground, when all of a sudden he stopped. Despite Cal's best efforts to pull on the leash, the cat refused to move — he'd lowered his body as if he were hunting something, his wide head close to the ground and his skeletal tail sticking straight out behind him. His ears were pointing and twitching like radar dishes.

  "Where are they," Cal whispered frantically. Will didn't answer but instead reached into the side pockets of Cal's backpack and yanked out two large firecrackers. He also took out Auntie Jean's little plastic disposable lighter from an inner pocket in his jacket and held it ready in his hand.

  "Come on, Bart," Cal was whispering into the cat's ear as he knelt beside him. "It's all right."

  What little hair Bartleby had was bristling now. Cal managed to draw the cat around, and they tiptoed in the opposite direction as if walking on eggshells, Will at the rear with the firecrackers poised in his hands.

  They followed a wall as it curved gently around, Cal feeling the coarse masonry with his free hand as if it were some incomprehensible form of Braille. Will was walking backward, checking behind them. Seeing nothing but the forbidding clouds, and coming to the conclusion that it was futile to try to place any reliance on sight in these conditions, he spun around only to blunder into a granite plinth. He recoiled as the leering face of a huge marble head reared out of the parting mist. Laughing at himself, he warily stepped around it and found his brother waiting only a few feet ahead.

  They had gone about twenty paces when the fog mysteriously folded back to reveal a length of cobbled street before them. Will hastily wiped the moisture from his eyepieces and let his gaze ride with the retreating margins of the fog. Bit by bit the edges of the street and the facades of some of the nearest buildings came into view. Both boys felt an immense flood of relief as their immediate surroundings were tantalizingly revealed for the first time since they had entered the city.

  Then their blood turned cold.

  There, not thirty feet away, only too real and horribly clear, they saw them. A patrol of eight Styx were fanned out across the street. They stood motionless as predators, their round goggles watching the boys as they dumbly looked back.

  They were like specters from some future nightmare in their gray-green striped long coats, strange skullcaps, and sinister breathing masks. One held a ferocious-looking stalker dog on a thick leather strap — it was straining against its collar, its tongue lolling obscenely out of the side of its monstrous maw. It sniffed sharply and immediately whipped its head in the boys' direction. The black pebbles of its beady eyes sized them up in an instant. With a deep, rumbling snarl it curled back its lips to reveal huge yellowing teeth dripping with saliva. Its leash slackened as it crouched down, preparing to pounce.

  But nobody made a move. As if time itself had stopped, the two groups merely stood and stared at each other in horrible, mute anticipation.

  Something snapped in Will's head. He screamed and spun Cal around, knocking him from his shocked inertia. Then they were running, flying back into the fog, their legs pumping frantically. They ran and ran, unable to tell how much ground they were covering through the shrouds of mist. Behind them came the savage barking of the stalker and the crackling shouts of the Styx.

  Neither boy had a clue where they were heading. They didn't have time to think, their minds frozen with blind panic.

  Then Will came to his senses. He yelled at Cal to keep going as he slowed to light the blue fuse on a huge Roman candle. Not really certain if he'd lit it, he quickly dropped it against a chunk of masonry, angling it in the direction of their pursuers.

  He ran ahead several feet, then stopped again. He flicked the lighter, but this time the flame refused to come. Swearing, he struck it desperately again and again. Nothing, just sparks. He shook it just like he'd seen the Grays do so often at school when lighting their illicit cigarettes. He took a deep breath and once again spun the tiny wheel. Yes! The flame was small but enough to ignite the fuse of the firecracker, an air-bomb battery. But now the snarling and barking and voices were closing around him. He lost his nerve and simply slung the firecracker to the ground.

  "Will, Will!" he heard up ahead. As he homed in on the shouts, he was furious that Cal was making so much noise, though he knew he would never have found him otherwise. Will was running at full tilt when he caught up with his brother and almost bowled him over. They were sprinting furiously as the first firework went off. It screamed out in all directions, its bright primary colors bleeding through the texture of the fog before it ended with two deafening thunderclaps.

  "Keep going," Will hissed at Cal, who had crashed headfirst into a wall and was acting a little stunned. "Come on. This way!" he said, pulling his brother by the arm, not allowing him any time to dwell on his injury.

  The fireworks continued, exploding fireballs of light high into the cavern or in low arcs that ended in the city itself, momentarily silhouetting the buildings like the scenery in a shadow play. Each iridescent streak culminated in a dazzling flash and a cannon-shot explosion, echoing and rumbling back and forth through the city like a raging storm.

  Every so often, Will stopped to light another firecracker, picking out Roman candles, air bombs, or rockets, which he positioned on pieces of masonry or threw to the ground in the hope of confusing the patrol as to their position. The Styx, if they were still following, would be bearing the brunt of this onslaught, and Will hoped that at the very least the smell of the smoke might put the stalker off their scent.

  As the last of the fireworks exploded in a cavalcade of light and sound, Will was praying he'd bought them enough time to reach the Labyrinth. They slowed to a jog to allow themselves to catch their breath, then stopped altogether to listen out for any sign of their pursuers, but there was nothing now. They appeared to have shaken them off. Will sat down on a wide step of a building that looked like it could have been a temple and took out his map and compass while Cal kept watch.

  "I've no idea where we are," he admitted, tucking the map away. "It's hopeless!"

  "We could be anywhere," Cal agreed.

  Will stood up, looking left and right. "I say we carry on in the same direction."

  Cal nodded. "But what if we end up right back where we started?"

  "Doesn't matter. We've just got to keep moving," Will said as he set off.

  Once again the silence crowded in on them, and the mysterious shapes and shadows appeared and softened as if the buildings were pulling in and out of focus in
this invisible city. They'd made tortuously slow progress through a succession of streets when Cal came to a standstill.

  "I think it's clearing a little, you know," he whispered.

  "Well, that's something," Will replied.

  Once again Bartleby stiffened and crouched down low, hissing as the margins of the fog rolled back before them. The boys froze, their eyes feverishly raking the milky air.

  As if veils were being lifted to reveal it, there, not twenty feet away, a dark, shadowy form was hunched menacingly. They both heard a low, guttural growl.

  "A stalker!" Cal gulped.

  Their hearts stopped with awful realization. They could only watch as it rose up, its muscular forelegs tensing into life as it pawed the ground, then began to move, accelerating forward at a bewildering speed. There was absolutely nothing they could do. There was no point in running; it was too close. Like an infernal steam engine, the black hound was pounding toward them, condensation spewing from its flaring nostrils.

  Will didn't have time to think. As he saw the dog spring, he dropped his backpack and shoved Cal out of the way.

  The stalker soared through the air and slammed heavily against Will's chest. Its clublike paws knocked him flat on his back, his head thwacking the algae-covered ground with a hard slap. Half stunned, Will reached up and grasped the monster's throat with both hands. His fingers found its thick collar and hung on to it as he tried to hold the brute away from his face.

  But the animal was just too powerful. Its jaws snapped at his mask, then caught on to it and bit down. Will heard the squeal of its fangs tightening on the rubber as the mask was crushed against his face, and then a pop as one of the eyepieces shattered. He smelled the putrid breath of the stalker, like warm, sour meat, as the animal continued to wrench and twist the mask, the straps behind Will's head stretched almost to the breaking point.

  Praying the mask would stay in place, he tried with all his might to turn his head away. The stalker's jaws slid off the wet rubber, but Will's success was short-lived. The dog pulled back slightly, then immediately lunged again. Screaming, and still hanging on to its thick collar with all his might, Will was barely managing to keep it away from his face, his arms at the very limit of their strength. The collar was cutting into his fingers — he couldn't believe how heavy the beast was. Time after time, Will whipped his head away, only just evading the snapping teeth, like the jaws of a powerful trap clapping shut.

  Then the animal contorted and twisted its body.

  One of Will's hands lost its grip, and with nothing to hinder it the animal quickly sought out a more rewarding target. It caught hold of Will's forearm and bit down hard. Will cried out from the pain, his other hand involuntarily opening and letting go of the collar.

  There was nothing to stop it now.

  The animal instantly scrabbled over him and sank its incisors into his shoulder. Amid the growling and biting he heard the cloth of his jacket rip as the huge teeth, like twin rows of daggers, penetrated and tore into his flesh. Will wailed again as the animal shook its head, snarling loudly. He was helpless, a rag doll being shaken this way and that. With his free arm, he punched weakly at the animal's flanks and head, but it was no use.

  Then suddenly the dog detached itself from his shoulder and reared up over him, its huge weight still pinning him down. As its frenzied eyes fixed on his, he could see its slathering jaws just inches from his face, strings of its drool dripping into his eyepieces. Will was aware that Cal was doing all he could to help; he was quickly lunging in to pummel and kick at the beast, then just as quickly pulling back. Each time he did this, the dog merely half turned to snarl at him, as if it knew Cal posed no threat. Its small, savage brain was fixed on only one thing; the kill that was completely and utterly at its mercy.

  Will tried desperately to roll over, but the creature had him pinned to the floor. He knew he was no match for this unstoppable hellhound that seemed to be made from huge slabs of muscle as hard and unyielding as rock.

  "Go!" he yelled at Cal. "Get away!"

  Then, from out of nowhere, a fleshy bolt of gray catapulted a the stalker's head.

  For one instant, it was as though Bartleby was suspended in midair, his back arched over and his claws extended like cutthroat razors just above the stalker's head. The next, he'd dropped, and there was a shocking frenzy of movement. They heard the wet slicing of flesh as Bartleby's teeth found their first mark. A dark fountain of blood was jetting over Will from a livid gash where the dog's ear had been. The beast let out a low-pitched yelp and immediately bucked and leaped off Will, Bartleby still clamped to its head and neck, blitzing it with bites and savage flesh-tearing slashes from his raking hind feet.

  "Get up! Get up!" Cal was shouting as he helped Will to his feet with one hand and retrieved his backpack with the other.

  The boys retreated to a safe distance, then stopped, compelled to stay and watch. They were rooted to the spot, transfixed by this brute battle between cat and dog as both writhed in mortal combat, their shapes melting together until they became an indistinguishable whirlwind of gray and red, punctuated by flashing teeth and claws.

  "We can't stay here!" Will yelled. He could hear the shouts of the approaching patrol, which was quickly homing in on the fight.

  "Bart, leave it! C'mere, boy!"

  "The Styx." Will shook his brother. "We have to go!"

  Cal reluctantly moved on, peering back to see if his cat was following through the mist. But there was no sign of Bartleby, only the distant hisses and yelps and screeches.

  Shouts and footfalls were now echoing all around. The boys ran blindly, Cal grunting with the effort of carrying both packs, and Will trembling with shock, his whole arm throbbing dully with pain. He could feel the blood streaming down his side and was alarmed to find that it was running over the back of his hand in small rivulets and dripping from the ends of his fingertips.

  Out of breath, the boys hastily agreed on a direction, hoping against hope it would take them out of the city and not straight back into the arms of the Styx. Once on the marshy perimeter, they would make their way around the edge of the City until they found the mouth of the Labyrinth. And if worse came to worst and they missed it completely, Will knew they would eventually comet to the stone staircase again and could quickly return Topsoil.

  From the sounds they were hearing, the patrol seemed to be zeroing in on them. The boys were dashing at full speed, but then they blundered into a wall. Had they inadvertently strayed down a blind alley? The terrible thought struck both of them at the same time. They frantically felt along the wall until they found an archway, its sides crumbled away and the keystone missing at its apex.

  "Thank God," Will whispered, glancing at Cal with relief. "That was close."

  Cal merely nodded, panting heavily. They peered briefly behind them before passing through the ruined archway.

  With lightning speed, strong hands grabbed them roughly from either side of the opening, yanking them off their feet.

  35

  Using his good arm, Will lashed out with all the strength he could summon, but his knuckles just grazed ineffectually off a canvas hood. Their captor cursed sharply as Will followed with another blow, but this time his fist was caught and trapped in the iron grip of a huge hand, forcing him back effortlessly until he was pinioned against the wall.

  "That's enough!" the man hissed. "Shhh!"

  Cal suddenly recognized the voice and began pushing in between Will and his hooded assailant. Will was completely baffled. What was his brother doing? Feebly he tried to lash out again, but the man held him fast.

  "Uncle Tam!" Cal shouted joyously.

  "Keep it down," Tam rebuked.

  "Tam?" Will repeated, feeling all at once very stupid and very relieved.

  "But… how… how did you know we'd be…? Cal stuttered.

  "We've been keeping an eye out since the escape went off the rails," their uncle cut in.

  "Yes, but how did you know it was us? C
al asked again.

  "We just followed the light and the noise. Who else but you two would use those bloody fool pyrotechnics? They probably heard it Topsoil, let alone in the Colony."

  "It was Will's idea," Cal replied. "It sort of worked."

  "Sort of," Tam said, looking with concern at Will, who was steadying himself against the wall, the rubber of his mask scored with deep gouges and one of his eyepieces shattered and useless. "You all right, Will?"

  "I think so," he mumbled, holding his blood-soaked shoulder. He felt a little woozy and detached, but couldn't tell if this was because of his wounds or because of the overwhelming sense of relief that Tam had found them.

  "I knew you'd not be able to rest with Chester still here."

  "What's happened to him? Is he all right?" Will asked, perking up at the mention of his friend's name.

  "He's alive, at least for the time being — I'll tell you all about it later, but now, Imago, we'd better make ourselves scarce."

  Imago's massive form slipped into sight with unexpected fleetness, his baggy mask twisting furtively this way and that, like a partially deflated balloon caught in the wind, as he scrutinized the murky shadows. He swung Will's pack over one shoulder as if it weighed nothing, and then he was off. It was all the boys could do to keep up with him. Their flight now turned into a nerve-racking game of follow the leader, with Imago's shadow piloting them through the miasma and unseen obstacles while Tam brought up the rear. But the boys were so very grateful to be back under Tam's wing that they almost forgot their predicament. They felt safe again.

  Imago cupped a light orb in his hand, allowing just enough light to spill from it so they could negotiate the difficult terrain. They jogged through a series of flooded courtyards, then left the fog behind as they entered a circular building, racing at a staggering pace along corridors lined with statues and flaking murals. They slid in the mud on the cracked marble masonry until they found themselves hurtling up stairs of black granite. Climbing higher and higher, they were suddenly out in the open again. Traversing fractured stone walkways that had long sections of their balustrades missing, Will was able to look down from giddying heights and catch views of the city below between the meshing clouds. Some of these walkways were so narrow Will feared that if he hesitated for a second he might plunge to his death in the foggy soup that masked the sheer drops on either side. He kept going, putting his trust in Imago, who didn't waver for an instant, his unwieldy form driving relentlessly ahead, leaving little eddies of fog in its wake.