The sky-scholars, on the other hand, maintained that if they did not do just that, Sanctaphrax would break from its moorings and be lost for ever. In the event, the debate never reached a final vote, for the sky-scholars – convinced that they were correct and terrified of becoming lost in open sky – enlisted the help of a band of flat-head goblins to carry out their plans.

  At first light on that fateful day, the flat-heads broke in and forcibly removed the earth-studies scholars from their Great Laboratory. By noon – for the first time in the history of Sanctaphrax – the sky-scholars were in complete control of the floating rock. They had a chest of stormphrax carried down the tunnels to the newly-created Treasury and, having determined the exact centre of the chamber, aligned it carefully. A company of guards was left to ensure that no-one tried to sabotage what they had done – a company later to become the much-feared Treasury Guard.

  All this happened many many years ago, with all the protagonists now long since dead and consigned to history books and civic records. Yet certain aspects of that special day remained, enshrined in tradition, rituals – and even in the language. A cry of Trust the skies! for instance, took on the meaning of ‘Good luck!’ while ‘Librarian's loss!’ meant the opposite, both in Sanctaphrax and, later on, in Undertown. Treasury Day, as it had become known, was a holiday marked by many with message-sending and gift-swapping, and was celebrated in the refectory with a seven-course banquet.

  More relevantly, it was also the day when the Treasury Guard and Chamber were ceremoniously inspected by the so-called Next-Most High Academe. From early morning, crowds would gather outside the entrance to the treasury tunnel – festooned for the occasion with flags and bunting – to watch and cheer on the spectacle.

  ‘An excellent turn-out this year,’ said the Professor of Light from the stately prowlgrin-drawn carriage which – at precisely three hours – was rolling into the Mosaic Quadrangle.

  ‘Excellent indeed,’ said the Professor of Darkness as he pulled up the sleeves of his fur robes and waved back regally to the cheering onlookers. ‘And perfect weather for it, too, now that those rainclouds have cleared.’

  The carriage continued across the intricate tiled mosaic and on towards the pyramid-shaped entrance. The spectators fell back excitedly as it clattered towards them. Seven strides from the doorway, the prowlgrin halted and the two professors stepped down onto the red and gold carpet awaiting them.

  From his viewpoint on the steps of the Great Hall, Quint was enthralled. He had never witnessed such pomp and splendour before. ‘Look at the prowlgrin!’ he said excitedly. ‘Those look like real marsh-gems and mire-pearls on its bridle.’

  ‘I'm sure they are,’ said Maris.

  ‘And the professors' robes!’ said Quint. ‘Can that really be genuine pine-ermine?’

  ‘Of course,’ said Maris. ‘A white winter pelt for the Professor of Light, and a black summer coat for the Professor of Darkness.‘

  Quint nodded and fell silent – though not for long. ‘I don't get all this Next-Most High Academe business,’ he said. ‘Why doesn't the Most High Academe perform this ritual himself? And why are there two of them?’

  ‘You've so much to learn,’ said Maris in a rather superior voice, ‘but if you keep on chattering, you'll miss the ceremony. Hush, here they come now.’

  ‘So-rry,’ said Quint sullenly. ‘I shan't say another word.’

  ‘Good,’ said Maris primly, patting her damp hair and straightening her steaming robes. ‘It's Treasury Day and I have to keep up appearances.’ She acknowledged a wave from the Sub-Professor of Mistsifting with a dignified nod. ‘After all, I am the daughter of the Most High Academe…’

  A stooped figure with a hooded cape and silver nose-piece who was standing on the step directly below them turned to face them. ‘Forgive me for interrupting,’ he said, his voice deep and gruff, ‘but the lad does have a point. We accept what's going on so blindly these days. Perhaps one ought to question a little more.’

  Maris snorted and turned away. Quint drew closer. ‘Do you know any of the answers?’ he asked the stranger.

  ‘Some,’ he said. ‘For a start, the Next-Most High Academe was originally chosen because at the time the Great Laboratory became the Treasury Chamber, the Most High Academe was an earth-studies High Librarian. For this reason, a sky-scholar was selected to ensure that the new Treasury was adequately guarded. Nowadays, of course, the Most High Academe himself is a sky-scholar, and the role of the Next-Most High Academe little more than theatre.’

  Down at the entrance to the treasury tunnel, the two professors were hammering, slowly and simultaneously, on the door with their staves. Once. Twice. Three times. As the loud, resonant thuds faded away, the quadrangle fell still. Then, out of the silence, came a muffled voice.

  ‘Who goes there, by Sky?’ it demanded.

  ‘A friend of Sanctaphrax,’ the two professors shouted back in unison.

  There was a creak as the door swung open and a massive flat-head guard – with sword in one hand and studded cudgel in the other – stepped forwards to inspect them carefully.

  ‘Who's that?’ whispered Quint.

  ‘Sigbord, the chief guard,’ Maris whispered back.

  The crowd remained still, scarcely daring even to breathe. Then the flat-head lowered his weapons and spoke up.

  ‘Enter, friend!’ he proclaimed, and a roar of approval echoed round the quadrangle.

  The two professors disappeared inside, the door slammed shut behind them and the roaring of the crowd grew louder still. But Quint was puzzled.

  ‘A friend of Sanctaphrax,’ he repeated. ‘That's what the greeting said. Friend, not friends. So, how come there are two of them? Is it because they're twins?’

  ‘Oh, they're not twins, for all that they look so similar,’ the stranger with the silver nose-piece growled. ‘They met as young apprentices, drawn together by their shared interest in matters of luminescence. As time passed, they began to sound the same, even look the same …’ He glanced towards the door. ‘Like the subject they study, they're two sides of the same coin. It was impossible to appoint one of them to the post of Next-Most High Academe without appointing the other.’

  ‘I see,’ said Quint. By now, the crowd was beginning to disperse. Quint was about to depart himself when the stranger gripped him by the arm.

  ‘Not that I am in any sense condoning the situation,’ he hissed.

  ‘I beg your pardon?’ said Quint stiffly, as he tried to shake his arm free. The stranger tightened his hold.

  ‘There are many,’ he said, his eyes darting around him, ‘who are suspicious of the influence the Professors of Light and Darkness have over the Most High Academe. After all, why has a mistsifter seen fit to take on advisers from another school? And why …’

  ‘Come on, Quint,’ Maris said sharply and suddenly, seizing him by the other arm. ‘We should be getting back.’ And with that, she dragged him away.

  As they joined the crowds – now spilling out of the Mosaic Quadrangle and going their separate ways – Quint glanced round.

  ‘What was the rush?’

  Maris turned to him. ‘He was starting rumours and spreading gossip, that's why I wanted to leave,’ she replied. ‘I‘ve heard it all a hundred times before. The whispers. The intrigue. The lies. The question is, what was he after?’

  As the door slammed shut behind them, the Professors of Light and Darkness relaxed. Since the rest of the annual ceremony would be performed out of sight of the excited spectators of Sanctaphrax, they had no need for any further pomp and ceremony. The Professor of Light removed his traditional white tricorn-hat and scratched his head.

  ‘So, Sigbord,’ he said, ‘have you any fresh news on the matter we were speaking about yesterday?’

  Sigbord was a large flat-head goblin, long-limbed and powerful; his many scars and intricate tattoos testified to a long career as a guard. He raised his lamp and turned.

  ‘I have, sir,’ he said, and looked round
furtively. ‘Two new developments. First,’ he whispered, ‘the mistsifters are up to something – and not just the apprentices. This one goes right up to the top. The Dean. The Sub-Dean. The Sub-Professor. One, two or possibly all three of them are involved.’

  The Professor of Light shook his head. ‘Linius should have noticed…’

  ‘And would have,’ the Professor of Darkness broke in, ‘were he not so preoccupied. Poor fellow. He started out as Most High Academe so well – yet recently, he's been looking appalling…’

  ‘He never sleeps. He never eats,’ agreed the Professor of Light. ‘And though I hate to say it of so old and valued a companion, he has been neglecting the duties of high office…’

  ‘That's because he spends so much time down in the cages studying Low Sky,’ said the Professor of Darkness hotly. ‘I just don't understand it.’

  ‘Neither do I,’ said the Professor of Light. ‘But as his two closest friends, we must persuade him to face up to his responsibilities.’

  ‘Sirs, you must also warn him,’ said Sigbord, and sighed. ‘He will not listen to me.‘

  ‘Warn him?’ they said in unison.

  ‘That was my second piece of information,’ Sigbord said urgently. ‘Someone has been trying to bribe the cage-guards…’

  At that moment, a grating sound came from the shadowy crevices of the tunnel, far to their right. Sigbord drew his sword, cocked his head to one side and listened. He turned back to the professors.

  ‘We must be discreet,’ he hissed. ‘Even here in the treasury tunnel, there are those who would not hesitate to make capital from an ill-chosen remark.’

  The Professor of Darkness frowned. ‘Are you suggesting that the treasury-guards are not now to be trusted?’ he whispered.

  Sigbord's voice dropped further. ‘I'm afraid I am, sir. The Most High Academe's curious behaviour is affecting all of Sanctaphrax. Morale among the treasury-guards is lower than I have ever known it.’

  They continued in silence, down the tunnel cut through the stonecomb and on to the heartrock at its centre. It was there – carved out of the solid rock – that the Treasury Chamber housed the sacred stormphrax. When it was first constructed, the tunnel had been completely straight, following the shortest route between the surface and the centre of the great Sanctaphrax rock. As time passed, however, this first tunnel within the stonecomb had begun to curve, to bend. That was the problem with tunnelling through rock which was still growing. What was more, as the porous rock continued to expand and shift, so the tunnel itself had threatened to close up as the ceiling lowered or the walls closed in; tunnel maintenance became a never-ending task.

  ‘I swear this tunnel gets longer each year,’ complained the Professor of Darkness.

  The Professor of Light nodded. ‘It's high time we had a new treasury tunnel built,’ he said. ‘Direct from the School of Light and Darkness.’ He looked round. ‘It would be difficult and costly, but well worth it.’

  The shifting expanse of stonecomb was as porous as a ball of brittle-sponge. Filled with cracks and cavities which linked up to form a sprawling intricate warren of tunnels and holes, it hummed and hissed endlessly. Some of the tunnels were large enough for a person to proceed comfortably through the rock; others were too small even for the tiny spider-shrews – of which there were many – to squeeze into. It was a vast, confusing maze, everchanging, full of echoes and whispers, shadows and strange beings which glowed in the darkness. Some were ghostlike, some half-formed – and some predatory.

  Ahead of them came the sound of muffled voices. At the same time, the stonecomb gave way to the hard, deep-red heartrock.

  ‘Thank goodness for that,’ said the Professor of Darkness as he continued down the long, straight passageway, running his fingers along the smooth solid rock. ‘The stonecomb always gives me the jitters.’ He chuckled. ‘I'm far too unfit to outrun a glister!’

  The voices ahead of them grew louder and, as they neared the end, a great studded door opened to their right and yellow light fanned out over the floor. A heavily-built flat-head guard stepped out and blocked the passage.

  ‘Halt!’ he ordered. ‘Who comes this way?’

  Sigbord stepped forward. ‘It is I, Mogworm,’ he said angrily. ‘Have you forgotten what day it is?’

  ‘No, sir … I …’ said Mogworm. His voice was gruff, and heavy with the rich, ponderous accent of the Deepwoods flat-heads. He looked at the professors and jutted his chin towards them. ‘Who are these two?’

  Sigbord sighed and turned to the professors. ‘Excuse him,’ he said. ‘He's new to the guard.’ He turned back to the goblin. ‘Today is Treasury Day, Mogworm. The day of the year when the Next-Most High Academe ceremonially inspects the stormphrax.’

  Mogworm looked down. ‘How was I supposed to know?’ he muttered.

  ‘Because,’ said Sigbord, ‘I reminded you only this morning. Now step aside and let us pass.’ Mogworm fell back, and as Sigbord strode past, he cuffed him around the head. ‘Imbecile!’ he growled, and turned to the professors. ‘Like I said, he's new to the guard. Fresh out of the Deepwoods, in fact. Strong in the arm, but soft in the head, that's his trouble. But he'll learn.’

  He turned and continued down the corridor, past a huge carved door, half open. The professors hurried after him, their gowns flapping. As they passed the door, they glanced in to see a long, rounded chamber carved out of the solid rock.

  This was the guard-room, home to a company of hand-picked flat-head goblins who divided their guard-duty into three shifts. Some guards were snoring in bunk-beds cut into the walls of the chamber, some were at a table playing cards, while the others – of whom Mogworm was one – were on duty. Like Sigbord, all of them were fearsome specimens.

  They reached the end of the corridor. Sigbord pulled a ring of keys from his belt, unlocked the door there and stood aside for the Professors of Light and Darkness to enter first.

  ‘It never fails to impress me,’ the Professor of Light whispered as he walked into the vast Treasury Chamber.

  ‘Absolutely awe-inspiring,’ the Professor of Darkness agreed.

  Across the floor they went, their footsteps echoing round the great domed ceiling. Beneath their feet, carved into the rock itself, was an enormous circular design of calibrated triangles, concentric rings and a fanned circle of lightning bolts. It was identical in design to the Quadrangle Mosaic. The two professors stepped forward to where a chest – ludicrously small for the room that contained it – stood in the very centre of the floor.

  ‘Douse your lamp,’ the Professor of Darkness instructed the flat-head goblin.

  Sigbord lowered the wick until the flame guttered and died. The Treasury was plunged into absolute darkness. The Professor of Light leaned forwards and raised the lid of the chest. Instantly, the entire chamber was lit up with the dazzling glow of the stormphrax it held. The two professors silently counted the shards of precious storm-phrax. When they had finished, they bowed their heads.

  ‘Light in the darkness,’ the Professor of Light whispered, as the ritual decreed.

  ‘Darkness in the light,’ the Professor of Darkness murmured in response.

  And with those words, the Treasury Day ceremony was complete.

  The Professor of Darkness lowered the lid. Sigbord relit his lamp.

  Outside in the tunnel, the door once again shut, the guard turned to the professors. ‘Takes my breath away, that stormphrax. Every year. It really does. Never seen anything so beautiful.’ He paused. ‘Though what I don't understand is, how can such a small amount of that stormphrax stuff weight down this whole great floating rock of ours?’

  The Professor of Light smiled. ‘A thimbleful of stormphrax weighs more than a thousand ironwood trees…’

  ‘When in absolute darkness,’ added the Professor of Darkness.

  ‘Precisely,’ said the Professor of Light. ‘It is a wonder of sky science, Sigbord. Just as hot rock sinks and cold rock rises…’

  ‘And lufwood becomes buoy
ant when burned,’ added the Professor of Darkness.

  ‘But we must be ever-vigilant,’ the Professor of Light said thoughtfully. ‘Since the great floating rock is constantly growing, we shall need increasing amounts of stormphrax to hold it in place. The cloudwatchers yesterday confirmed that there has been a recent increase in sourmist particles coming in from the Edge.’

  ‘A Great Storm is on its way,’ said the Professor of Darkness.

  ‘Precisely,’ said the Professor of Light. ‘Garlinius Gernix is about to be sent from the Knights' Academy to the Twilight Woods in search of fresh stormphrax.’ He turned to the goblin guard. ‘Beautiful stormphrax, Sigbord,’ he said. ‘The most precious substance in sky or earth, formed only in the Twilight Woods from the lightning bolts of a Great Storm…’

  Sigbord scratched his head. ‘It's all beyond me, Professor. I leave such learned matters to you academics,’ he said. ‘I'm just a simple guard.’

  ‘Pfff! You are being too modest, Sigbord,’ said the Professor of Light. ‘You are our eyes and ears.’

  ‘Without you,’ said the Professor of Darkness, ‘we would know neither about the treacherous mistsifters, nor about the attempts to bribe the cage-guards.’

  ‘But forewarned is forearmed, as the saying goes,’ said the Professor of Light. ‘We will alert the Most High Academe at the earliest opportunity. He must be told of the great danger he is in.’

  · CHAPTER NINE ·

  THE STONECOMB

  For the third time in as many nights, Quint's dreams were disturbed. It was at four hours when the soft tap-tap-tap on the door of his bed-chamber roused him from sleep. He rolled over and peered across the gloomy room.

  ‘Who is it?’ he mumbled sleepily.

  The tapping grew louder, more insistent.

  ‘I said, who is it?’ Quint called back, louder.

  ‘Quint, are you in there?’ came an urgent voice.

  ‘Is that you, Professor?’ said Quint, sitting up. ‘Come in.’