'There's one more thing.'

'Go on.'

'I did a foolish thing, Malien. Minis swore on the ring I made him - this ring - that he would do everything in his power to save me. And . . .'

'What?'

'I didn't believe him. He's so weak. I tried to reinforce his vow for him. I - I swore by the amplimet-' Malien started. 'I swore by the amplimet that if he failed me, he'd rue it all his remaining days.'

'That was . . , not wise, Tiaan.'

Tiaan could see that she was disturbed. 'And surely, if he's alive, he does rue it.'

"'He may. So Vithis will track the amplimet and eventually discover that you came here. I won't be able to hold him back.'

'I'd better get going,' said Tiaan. 'I was expecting that. And, of course, the Well of Echoes-'

'It's stable now. I had a painful struggle after you left, before I tamed it, and more than once I thought it was going to defeat me. But what the amplimet did once, it may do again, and more quickly. It may have grown stronger too. Tell me, did it communicate with any other nodes?'

'Yes, at Nyriandiol and Snizort. But not since the Snizort node exploded.'

'I heard about that,' said Malien, shaking her head. 'Was it a unique problem, with that node, or might all nodes be at risk? I must take advice on the matter.'

'Is it safe for me to stay till the morning?' Tiaan said wistfully. 'I so long to sleep in a bed and not be afraid of what's out in the dark, hunting me. I've not felt secure since I left here.'

'You may sleep in perfect ease. In the morning we'll leave Tirthrax for somewhere safer.'

'You're coming with me?' Tiaan could not keep the joy out of her voice.

'Someone has to look after you,' Malien said dryly. 'Go up.

Your old room is ready and I've laid out clean clothes for you.'

How did you know I was coming?'

Vithis sent a skeet, ordering me to hold you if you came back. And indeed, where else could you have gone?'

'Where are we going?'

'To my own people, though I'm uncertain of the welcome either you or I will get there. Bathe and rest in security. I'll keep watch, if that comforts you. We're going to Stassor in the morning.'

Tiaan took out the amplimet, the other crystal, the helmet and the tesseract, and did as she was bade.

Malien woke Tiaan only minutes before dawn. To Tiaan's surprise, she was ushered into a different construct, which Malien had repaired during Tiaan's absence. Tiaan reached for the controls, discovered they were completely unfamiliar, and drew back. Malien motioned Tiaan into the seat beside her, took hold of a padded yoke and the machine lifted smoothly into the air.

'It flies!' Tiaan exclaimed.

'What we did together last winter rekindled my longstanding interest in the secret of flight. I feel quite rejuvenated.'

'Where did you find another amplimet?'

'I didn't. I use the Art in an entirely different way, if you recall. I've done so all my life. I found my own path to controlling a thapter.'

Tiaan was stunned. 'How long have you had this one working?'

'Three months, more or less, though I've tinkered with it nearly every day, improving it in various ways. Learning how to make your thapter fly was the hard part. Once we'd discovered that secret, making another was easy.'

'You once said you only had a minor talent for such work.'

'I dissembled. I've a very considerable talent, although for most of my life I've avoided using it.'

'Why, Malien?'

'You don't know your Histories well, do you?'

'Not of your time.'

'When I was young . . , well, younger, at any rate, I was partner to Tensor, a brilliant man but one whose obsession led the world to the abyss. The war, and the invasion by the lyrinx that led to it, arose out of his folly. Because he was obsessed with devices, I swore not to use my talent, and for more than two hundred years I have not.'

'And now?'

'Times change, and so must we, to suit them. Not using my talent for the cause I believe in would be just as great a folly.'

'Does Urien know about your thapter?'

'No. I had warning of her messengers, so I made sure it looked innocuous. Even had they gone inside, they could not have flown it. It's designed to be controlled by my mind, and mine alone.'

'What if I were to put in my amplimet?' said Tiaan forlornly. She'd thought, after coming to Tirthrax, that she might obtain another set of carbon whiskers and diamond crystals, and make her construct fly.

'I wouldn't want to risk my life that way. Should it become necessary, I'll make changes so you can fly it.'

Passing through the entrance, which was hung with blue icicles as long as Tiaan was tall, Malien turned the thapter over the great Tirthrax glacier and followed it, winding up into the high mountains, until the air grew so thin that Tiaan's every breath was an effort. Malien did not seem to be troubled, but she had lived in the mountains all her life. It grew bitterly cold, even with the hatch closed.

'Go below,' the Aachim said. 'Pull out the bunk at the rear. It's warmer there.'

Tiaan did so. It lay directly above the mechanism that drove the thapter but, even so, wrapped in blankets, Tiaan was cold. She lay down and closed her eyes, fretting. All the Tirthrax Aachim had gone to Stassor the year before last, to a great meeting about the war. Only Malien had remained in Tirthrax. Though she was venerated as a hero from the Histories, her own people did not trust her. She had not been welcome at their meet, so how could Tiaan be?

Stassor lay within the great mountain chain that ran down the eastern side of Lauralin, from beyond Tiksi in the south, all the way to the north-easternmost tip of the continent at Taranta. In a straight line, Stassor was about two hundred and forty leagues from Tirthrax, but they could not travel in a straight line.

First they had to cross the Great Mountains, which were so high that not even Malien could breathe at their summits. She had to travel a winding course along glacier-filled valleys, with bare ridges as sharp as flakes of flint towering above them on either side, and then across the high plateau, the most inhospitable environment in the world. That rugged land was perpetually sheathed in ice. Nothing grew there. Nothing could have lived there, unless it had crept out of the void through some dark aperture when the Way between the Worlds was open, and delved deep into the underlying rock to suck at the warmth, and brood.

Malien dawdled, as if no more anxious to reach Stassor than Tiaan was. She ventured up every icy valley to its vantage point, sometimes only travelling for an hour or two before stopping to spend the rest of the day at some spectacular lookout, wrapped in her blankets and silently taking in the scene. It felt like a farewell journey, a final visit to everything that was beautiful and unspoiled. The trip took twenty-one days, though only after fifteen had passed did Tiaan shake free from the helpless terror that had controlled her life since Gilhaelith had been taken from ooreah Ngurle many months ago. For the first time she felt safe. Who would not, with Malien looking after them? No one could have tracked them across this wasteland. No construct could cross the Great Mountains. They were impassable on foot, by any land conveyance and even by air-floaters, since the lowest passes were higher than such machines could rise.

Malien did not question Tiaan about the intervening months, though she did show an unexpected interest in Gilhaelith. 'Where did he come from, do you think?'

'Somewhere on Meldorin. He would not talk about his past, more than I've told you.'

'An interesting man,' said Malien. 'And not entirely old human, surely. I wonder what his lineage is?'

'What do you mean?' said Tiaan.

"To have lived so long, surely he must have blood of the longer-lived species in him - Aachim or Faellem, or even Charon.'

Tiaan had not thought about that. 'But mancers can lengthen their own lives.'

'More lose their lives in the attempt than survive it, so it's attempted less often than you might imagine. And even at its best it rarely returns them to their youth. A hale middle age is the most that can be expected. For the unfortunate, however, it means death, or worse.'

'What could be worse?'

'Ending up as a monstrosity with your body parts in the wrong places, begging for release and being unable to find it.'

'Well, Gilhaelith's dead, so it doesn't matter,' said Tiaan after a long silence. He was another painful memory. It reminded her of the one man who hadn't let her down: Merryl, last seen trudging around the side of the hill near Snizort. Had he just exchanged one form of slavery for another?

'How do you know?' said Malien.

Tiaan came back to the present. 'I don't suppose I do . . .'

'The matriarch of Snizort went to great lengths to abduct Gilhaelith. Surely, when she fled the tar pits, she took him with her.'

'And yet they left me behind.'

'That could have been confusion when Snizort was attacked.'

'Or because the torgnadrs they patterned on me turned out to be useless!'

Forty-eight.

Tiaan did not know what to expect of Stassor, except that it would be striking, beautiful and different, for each of the Aachim cities was unique. Tirthrax, carved out of the mountain's heart, bore no resemblance to the towers, pavilions and kidney-shaped dwellings she had seen in paintings of Aachan. Different again was Shazmak, their abandoned city on an island in the middle of the gorge of the River Garr, in the mountains of Meldorin. Tiaan had seen images of it in Tirthrax. Shazmak was a place of breathtakingly slender towers and pinnacles connected by swooping and coiled aerial walkways that looked as though they were made of glass. The city appeared so delicate that it might have been broken by a tap with a hammer, yet it had endured the gales for a thousand years. And still, in the end, it proved no match for treachery. The city's betrayer had been one of its own.

She was thinking these gloomy thoughts as they descended a long black slope streaked with ice, at the base of which lay an ice-filled basin bounded by crevasses. A glacier flowed out of its downhill lip. In the distance, partly concealed by a razor-topped ridge, Tiaan saw an isolated steep-sided mountain with four individual peaks, inside which nestled a field of ice. She surreptitiously checked the amplimet but it wasn't glowing at all. That didn't comfort her. Tiaan was beginning to feel that it was waiting for something; lurking; even preying.

As they approached the mountain with four peaks, Tiaan realised that the material between them was not ice at all, rather a vast silvery cube that reflected first one peak and then another, so that the whole top of the mountain appeared to shift before their eyes.

'Behold Stassor' said Malien. 'The greatest of our cities now.'

'It's nothing like I expected,' Tiaan murmured. 'It's so plain, so simple! Do the Aachim no longer care about their art and craft? In Tirthrax, every surface was decorated, every space shaped to perfection.'

'Time moves on and so must we. We yearn for simplicity now. Stassor is a new city built on the foundations of the old, but it has a beauty of its own. You'll see.'

'Tirthrax was hidden inside a mountain, yet Stassor stands on the highest peak around, for all the world to see. Do your people feel more secure these days?'

'Who could threaten us here? Not even a construct could climb these rugged passes, and what army could lay siege to Stassor? This entire land,' said Malien, a sweep of her arm indicating the white-tipped ranges on every side, 'is our land, and no one may cross its borders without our knowing.

'Besides, we no longer care to hide from the world. For thousands of years we looked back to Aachan, but our future is bound to Santhenar now. From the breaking of the Forbidding, two centuries ago, we began to take down old Stassor and build it anew, to celebrate our coming out. Do you not see its beauty now?'

The thapter had curved across a vast valley steeped in snow and up the other side, towards the four-peaked mountain. Tiaan caught her breath. With every movement the ice-coloured cube shimmered with colour - now like oil on water, now like the iridescence of a beetle's wing-case, now like the light of the sun fading from the sky. There were colours and patterns within its depths, too, and they resembled the shifting lines of sand on a wave-swept beach, or the flickering flames of a camp fire, or the play of colours in precious opal.

The thapter lifted sharply on an updraught. Tiaan's stomach lurched but Malien steadied the machine expertly and directed it towards the base of the great building, where a pattern of smaller cubes appeared to indicate an entrance.

She brought the thapter to ground on a paved rectangle outside the smaller cubes. Best if we show ourselves as friendly,' said Malien. 'My people have not seen a flying machine before. At least, not since Rulke was slain, and his was a weapon of war. Tiaan, I ask only one thing - that you say nothing about my part in the creation of this thapter.' Of course,' said Tiaan, 'but why?'

'My people may well suspect that I made it, but it would be better if they did not know. That way-' She broke off as shadows appeared behind the smaller cubes. 'Later' Tiaan reached for the pack containing the amplimet and her other possessions. 'Leave everything,' said Malien. 'They will be brought, after inspection.'

Were the Aachim just being careful or were they, for all their brilliance, insecure? Tiaan was reluctant to leave anything behind, least of all the perilous amplimet, but there was no alternative. She climbed down onto the platform, which was made of compressed ice. It was bitterly, bone-achingly cold outside, far worse than Tirthrax, and the air so thin that just placing one foot in front of another was exhausting.

As they approached the entrance, a dark line divided it vertically into two halves, which separated into four individual cubes on either side, and each of those into four more, a pattern which Malien described as cubular. The myriad glassy cubes seemed to float through the air, leaving an opening which exhaled a breath of warmth. Tiny crystals of ice whirled and tumbled and twinkled in the sunlight. Gilhaelith would have been enchanted, Tiaan thought. The tetrarch had an obsession with numbers.

'Come,' said Malien, and they entered. 'I'm afraid.'

'Just so Karan and Llian must have felt as they entered the forbidden city of Shazmak. But they were met there by Rael, my son, and treated with all the hospitality due to visitors, even unwelcome ones such as I.'

'What happened to him?' asked Tiaan, not recalling that part of the tale.

'Alas, he drowned, nobly helping Karan and Llian to escape their fate. I still think about him every day. You need have no fear, Tiaan.' Her eyes glittered and she turned away.

'I would like to talk to you about that tale, sometime,' said Tiaan.

'I would be happy to. Have you read it?' 'The original is a forbidden book. There is a new Tale of the Mirror, but it was rewritten by the scrutators before my birth. Malien stopped in mid-step. 'Rewritten? The greatest of the Great Tales retold by a gaggle of spies and torturers? How did this come about?' 'I don't know.'

'Llian of Chanthed, who wrote the Great Tale, must lie uneasy in his grave,' said Malien.

'He's now known as Llian the Liar, the chronicler who debauched the Histories.'

'The Histories have indeed been debauched,' Malien said coldly. 'We must speak further about this. Ah, our hosts are coming.'

'Did you know Llian?' said Tiaan.

'As well as I knew any human man! The Histories were his life and his world. Nothing could have compelled him to tell them falsely.' 'But. . .' 'Later.'

Malien strode forward, holding out her hand to a stocky man of middle years, whose black hair was marked by twin streaks of white sweeping back over his ears. Half a dozen other Aachim stood behind him, three men and three women, all dressed in robes that reflected the light like metallic silk. 'Harjax,' Malien said cheerfully. 'I heard of your elevation. You will make a fine autarch.'

He took her hand, without enthusiasm. 'Thank you, Matah Malien. Why have you come, and how did you get here?'

'Come, Harjax, you've been observing us for ages. Tiaan Liise-Mar here, an artisan from the other side of the world has uncovered the secret of flight which has eluded all the mancers of this world, and Aachan, since the death of Rulke. In a short time she converted this construct, abandoned by Vithis in Tirthrax, into a machine that flies.'

'She may have assisted,' Harjax said, "but the mind behind this discovery was yours, Matah, as your hand was at the controls when it set down. What are you up to?'

'The secret of flight will benefit us all, Harjax.'

'Have you brought this thapter as a gift, then?'

'I had in mind to see what progress you'd made before-'