‘Quint!’ the professor barked. ‘I must speak with you!’

  ‘The door's not locked, Professor!’

  ‘Quint!’

  ‘Oh, for Sky's sake,’ Quint muttered as he climbed out of bed and trotted to the door. ‘I said, it's not … unkkh !’

  As he reached for the handle, the door burst open and sent him sprawling to the floor. The Most High Academe appeared in the doorway, a lantern in his hand. His face

  was drawn, yet flushed. His gleaming red-rimmed eyes looked feverishly round the room.

  ‘Quint, this is urgent,’ he said. ‘I need you to come with me. Immediately.’

  Quint nodded and climbed unsteadily to his feet. The door had dealt him a sharp blow to the side of his head. ‘Just let me get my things on,’ he said.

  ‘Quite, quite,’ came the distracted reply and, as Quint got ready, the professor hung his lantern on the wall and began pacing backwards and forwards across the room. ‘I haven't been able to sleep all night,’ he muttered agitatedly. ‘I doubt I shall ever sleep again, unless … unless I give it one more try.’ His words got faster, louder, more breathless. He paused and clutched his head in his hands.

  Quint watched him uneasily out of the corner of his eye as he buckled his boots, toggled his jerkin and fastened his belt. The venerable professor was quite clearly at the end of his tether.

  ‘Oh, forgive me for what I've done,’ he trembled. ‘For what I've unleashed …’ Quint said nothing. He knew the words were not intended for him. The professor resumed his pacing back and forwards, back and forwards. ‘It's so clever. So cunning. This is my last hope. Sky willing, I'll succeed this time. For if I fail…’ He turned to Quint and focused on the youth's face, as if seeing him for the first time. ‘I must succeed.’

  ‘Professor?’ said Quint.

  The professor retrieved his lantern ‘Come, lad,’ he said. ‘We have work to do.’

  It was dark outside, very dark; that darkest hour of the night just before the dawn. Apart from the professor's tallow-lantern, there wasn't a light to be seen and, as he followed the professor along the West Landing – its lamps now all extinguished – Quint stared up at the sky.

  It was the first time since his arrival in Sanctaphrax that the stars above had appeared as bright as they did from the deck of the Galerider. There, to the south, was the constellation of Borius the Spider. And there, Mitras the Great Banderbear. And further to the east was Darsh the Dragon, with the constant East Star currently forming the tip of its left wing.

  Quint sighed. When the lights of Sanctaphrax and Undertown were ablaze, the stars were all but invisible. He had badly missed their reassuringly familiar shapes. Yet now, seeing them once again, he realized that he missed both his father and his life on board the sky pirate ship even more.

  ‘Stop dawdling, Quint,’ the professor snapped from the spindly cage. ‘We haven't a minute to spare.’

  Quint trotted to catch up. This was neither the time nor the place for homesickness. His father had left him with the Most High Academe, and it was to him that Quint now owed his loyalty – at least for the time being. ‘I'm sorry, Professor, ' he said. ‘It won't happen again.’

  ‘I should hope not,’ the professor muttered as he stepped inside the cage. He lit the lamp and turned back to Quint. ‘If you get me down to the entrance to the tunnel as efficiently as you did last time, we'll say no more about it.’

  Quint nodded, wishing he had had the time to tell Maris of this new expedition. He took up his position at the weight-levers. ‘Release the winch-chain when I give the word, Profess—aaaagh! ‘he cried out as the rickety cage abruptly plummeted.

  Struggling to remain upright, Quint applied the brake-pedal with his foot while feverishly pushing and pulling at the weight-levers. Nothing happened. Had the cage broken away from its moorings completely?

  The chain rattled as it unwound; the framework creaked. Then, suddenly – with a loud grinding jangle – the lowsky cage gave an almighty lurch and began to slow down.

  ‘Thank Sky,’ Quint breathed. ‘I thought we were in trouble then. This old-fashioned type of flight mechanism can be very unpredictable, Professor.’

  Looking down from the West Landing, Bagswill, the flat-head guard, raised a fleshy hand and wiped away the beads of nervous sweat from his forehead.

  That was a close one, and no mistake, he thought. Why, the old cage might do the job on its own without his help. And that would never do.

  For Bagswill was ready and more than willing to tamper with the cage mechanism to bring about the tragic death of the Most High Academe – but the time had to be right. He had to have received payment for the task. Two hundred gold pieces he'd mentioned, and though the hooded character with the silver nose-piece had not exactly agreed, neither had he refused. It wouldn't do for the professor to die before Bagswill had concluded the deal. No, that wouldn't do at all. He would end up with nothing.

  He peered down at the stationary cage, far far below him. It looked so fragile. Chuckling unpleasantly, he turned and strode away. He had important business to attend to.

  With Quint back in full control, the descent had continued smoothly. Once again, the sky cage had come down just next to the entrance to the tunnel. Once again, the professor had used a tolley-rope to secure the cage to the jutting spur of rock. And once again, Quint had been left on his own as the professor scrambled onto the rocky ledge – stave in one hand and glowing tallow-lantern in the other – and disappeared into the tunnel entrance. This time, however, Quint did not stay in the sky cage.

  As the oily yellow lantern-glow and the tap-tap-tap of the stave both faded away, he reached over and – a little uneasily – unhooked the cage-lamp. Then, having checked that the tolley-rope which bound the cage to the rock would not slip free in his absence, Quint opened the door and stepped gingerly across onto the rocky ledge.

  A massive white raven which had been perched above the opening in the rock flapped up into the air. It wheeled round and, cawing furiously, divebombed the intruder.

  Quint ducked down and hurried into the tunnel. He raised his lamp – and gasped. This was his first time inside the great rock itself, inside the stonecomb, and it was extraordinary. Like a massive woodwasp's nest, full of chambers and tunnels, it seemed to continue for ever. The wind murmured and groaned as it passed through, and the tunnels glowed. Quint shivered uneasily. The stonecomb seemed almost to be alive.

  Wordspool's emphatic words came back to him once more. Sky-scholars don't go there.

  And neither do sky pirates, thought Quint. At least they shouldn't. Yet here he was standing at the edge of the treacherous labyrinth of narrow tunnels, any one of which could squeeze him to death or seal him up for ever if his luck deserted him inside the constantly shifting rock. Heart in his mouth, Quint set off.

  He hadn't gone more than a dozen strides when he came to not one, but three narrow passages fanning out in front of him. It was only the faint yellow lamplight glowing from the left-hand one that told him which to take. He hurried along it gratefully, but the incident was unnerving. It brought home to him just how easy it would be to become lost inside the shifting stonecomb, and he pulled a piece of black chalk from his pocket to mark his route.

  Centuries of unchecked and random rock-growth had left the tunnel twisting and turning through the great floating rock like a worm-hole in a woodsap. Deeper and deeper Quint went, pausing every few paces to mark the walls with rough arrows. Each time he stopped, Quint had the horrible feeling that he was being observed – yet, when he looked, there was never anything there. Nothing but the hissing and humming of the wind drifting through the glowing porous rock.

  Quint tried hard to keep up with the professor, marking the walls as quickly as he could and hurrying on. But the tunnel was difficult to negotiate. The ceiling was low; the floor was pitted and marked with countless protrusions which tripped him up and grazed his shins; while the walls were, in places, so close together that it was only by squ
eezing sideways between the rough surfaces that he was able to go on at all.

  The professor, Quint realized, must have removed the worst obstructions on earlier trips, because every so often he would come to sections where the rock was scarred by recent pick-axe blows and the ground was strewn with rubble and dust.

  All the while, the stonecomb echoed with curious groans and breathy murmurs. Could they really be caused by the wind alone? Quint found himself wondering, and his fingers trembled as he hastily scrawled another arrow on the uneven stonecomb wall.

  It was at the end of a relatively clear stretch of tunnel that Quint caught a glimpse of the professor's flapping gown. He hesitated, fell back and held his breath. He didn't want Linius Pallitax to know that he was being followed. Above the constant hum and hiss of the rock came the sound of impatient cursing. The professor's gown had become snagged on a jagged spur of rock.

  ‘Calm yourself, Linius,’ Quint heard the professor mutter as he tore the material free. ‘It'll be the worse for you if you arrive with your emotions in turmoil. Control yourself, or it will control you!’

  Quint frowned. What could he mean? There was only one way to find out.

  With shivers running up and down his spine, Quint scurried after the professor. The atmosphere in the tunnels grew warmer, stuffier. The humming grew louder while the hissing faded. The air glowed a deeper, darker red. All at once Quint rounded a bend to find that the professor had stopped in front of a stone door set into the solid rock, no more than a few strides away.

  He fell back and waited silently.

  The door was round in shape and seemed to have been constructed from the outer edge of the deep red heartrock itself. If it hadn't been for the innumerable creatures carved into its surface, the door would not have been visible at all.

  The professor approached the door. He clasped the Great Seal of Office which hung round his neck and leant forwards towards the carved stone. As he did so, Quint's view was obscured by the professor's hunched shoulders. The next instant, there was a low, grinding noise followed by a soft click – and the door slid open to reveal a vast, dimly-lit cavern.

  Craning his neck, Quint caught a glimpse of the curious sight within. There were countless gleaming flagons and glass spheres, all swaying at the ends of long, glowing stem-like tubes that protruded from the curved walls, and in the very centre of the chamber a huge glistening sphere, seemingly woven from light, hovered in mid-air.

  ‘What in Sky's name…?’ Quint breathed, crouching down and edging forwards for a closer look.

  And then he heard it: a low pitiful sound that sent shivers scampering up his spine, like the sobbing of an infant in pain. He shifted forwards for a closer look, but the professor was still blocking his view. Whatever was in there sounded small, vulnerable.

  ‘Be still, you evil creature,’ the professor snapped.

  As if in response, the plaintive cries turned into a hysterical high-pitched wail. And through the obvious distress, Quint thought he could hear words. Pleading. Imploring.

  ‘No more,’ it howled. ‘I beg you. No more …’

  Quint scrambled upright and was about to take a step forwards when the door abruptly slammed shut. The unhappy voice was instantly silenced and Quint was left staring at the circular design on the rock once more. He crept towards the door and pressed his ear against it, but the rock was too dense and too thick for any but the most muffled of sounds to penetrate.

  Quint turned away. The professor had something – or some one – locked up in this underground chamber. It was the last thing he'd expected and he shuddered uneasily, his head in a whirl. He had trusted Linius Pallitax, admired him even. Now he was unsure what to think.

  What had the professor got imprisoned inside the chamber? And what terrible experiments could he have performed on this creature for it to cry out so desperately? And what, it occurred to him with a jolt, was he to tell Maris – that her father was a madman who tormented luckless creatures in an underground torture chamber?

  One thing was certain. He had to get back to the lowsky cage before the professor. On no account must the Most High Academe discover, or even suspect, that he had followed him. Turning his back on the sealed chamber, Quint set off back along the corridor, vowing to return as soon as he could.

  He took turning after turning, sweating with a mixture of exertion and nerves. The rock hummed all round him as he followed the black arrows down the endless tunnels until…

  ‘Oh, Gloamglozer!’ he cursed as the familiar carved door in the rockface loomed up in front of him. ‘How did that happen?’

  Somehow, somewhere, he'd gone wrong and ended up back where he'd started. It was his own fault, he told himself angrily. He'd been so wrapped up in his thoughts of what was going on inside the chamber that he hadn't been paying proper attention to the trail he was following.

  He set off once more. This time he would have to concentrate. The Most High Academe could appear at any moment. He could not afford to mess up twice.

  Quint's heart began to race as he discovered how he'd gone wrong. Although he thought he'd marked the entire route from the entrance of the tunnel to the door of the chamber with small black chalk arrows, in his haste and nervousness, he'd drawn some so haphazardly that they hardly looked like arrows at all, while others were so faint that he could barely make them out. Moreover, in places the stonecomb was covered with marks of its own; dark stains, blots and blotches, black sooty smudges…

  Which marks had he made? he wondered. Which were there before?

  Worst of all, however, was the sudden realization that the rock itself had moved. Some of the narrow passages had become narrower still, while in places the low ceiling now forced him to stoop. Panic rose in his throat. Those groans he kept hearing – they weren't the wind, but rather the sound of the porous stonecomb growing, shifting, twisting out of shape. And if the walls were moving, then what hope was there of following the trail of arrows?

  ‘Which way do I go?’ he whispered, his voice low and tremulous as he came to a fork in the tunnel with identical black smudges apparently singling out both of them as the correct way to proceed. ‘I can only have drawn one of you,’ he groaned, ‘but which one?’

  He reached across, rubbed his index-finger over the first of the smudges and checked the tip. It was covered with a light powdering of black chalk.

  This way, then, he thought, turning to the tunnel on the left – but then he tried the second mark as well, just to be sure. He inspected his hand. Like the index-finger, his middle-finger was now coated in the same black chalky substance.

  ‘No!’ he cried out, and the explosion of fear and frustration echoed down the intricate catacomb of tubes, tunnels and galleries all round him – No No No No – before fading away, only to be replaced a moment later by a different sound entirely.

  It was the sound of scratching and scurrying. And it was coming closer.

  For a moment, Quint thought it must be the professor, hurrying back to the sky cage. But only for a moment. The noise wasn't coming from behind him at all, but from one of the two tunnels in front of him. Which one though? The echoing acoustics were so confusing.

  He stepped into the first tunnel, cocked his head to one side and listened. He frowned. It was impossible to be sure. He stepped back and was just about to inspect the left-hand tunnel when he saw a light approaching from the other end.

  Quint's heart missed a beat. Bright crimson and pulsing rhythmically, the light was speeding down the tunnel towards him. The sniffing and snuffling grew louder and louder.

  Without a second thought, Quint turned tail and dashed down the right-hand tunnel. The scurrying quickened and the air echoed with slobbery snuffling and leathery flapping. The creature – whatever it was – was giving chase.

  Glancing back over his shoulder, Quint stumbled, fell and gashed his right knee on a jagged rock where he landed. Thankfully, the lamp did not go out. The noises got closer still. The light behind him intensified.


  Heart in his mouth, Quint scrambled to his feet and, despite the searing pain in his knee, dashed off once more.

  ‘Faster,’ he urged himself, as he squeezed through a long, narrow stretch of tunnel and hobbled on. ‘Faster!’

  Behind him, the creature had paused. Quint heard sniffing, followed by loud slurping. He shuddered with disgust. It had found the place where he cut his knee.

  ‘Whiii-whiii-whiiiiii!’

  The excited high-pitched squeal resounded down the tunnel, filling Quint with absolute terror. Not only had the creature tasted his blood, but it had also liked it!

  Quint tore his scarf from his neck and, wincing with pain, tied it tightly round his knee to staunch the blood. He had to stop the trail of tell-tale red drops that he was leaving behind him, leading the creature on.

  Straightening up again, he limped off as fast as he could. His blood thudded in his temples. His heart hammered in his chest. All around him, above the sound of the humming rock, came the hissing of the wind once more. It was only now that it had returned that Quint realized it had been absent before. Something else was different too. The atmosphere was freshening, cooling. It could mean only one thing: he must be nearing the outer surface of the great rock.

  ‘Sky protect me,’ Quint murmured. ‘May I be heading towards the entrance I came in through and not some dead-end.’

  A moment later, he saw it.

  At first, his brain refused to accept what his eyes were telling him. He leant forwards and fingered the scrap of tattered material clinging to the jagged piece of rock. There was no doubt. This was where the professor had snagged his robes. He was following the right path. It was the first piece of good news Quint had had since entering the terrible dark, claustrophobic system of tunnels. What was more, behind him the throbbing red light and the disgusting slurping noises both seemed to be fading away. Had he given the creature the slip?

  The next moment he saw the light glowing ahead of him – and froze. Of course he hadn't! How could he even have considered it? Somehow, the fearsome creature had managed to get ahead of him. Staring fearfully at the light, he stepped slowly backwards. Noises behind him stopped him in his tracks. Flapping, snuffling, groaning… He spun round to see a second light, brighter than before. There must be two of them!