She tried to climb above it but only succeeded in dragging Gilhaelith through the crest. It broke over his head, drenching him. She let out a cry; her colours flashed and faded. He was sure she could not hold him. But Gyrull was not matriarch of a great and powerful race for nothing. Drawing on her last reserves of strength, she dug her claws further into his flesh, lifted him free of the water and slowly began to beat her way up.

The lyrinx surrounded her in a fluttering, spherical shell, offering their strength and shepherding her the last league to the shore of Meldorin. She hovered above a platform of yellow rock, a stone's throw from the water. Gyrull retracted her claws and Gilhaelith fell heavily, ruddy salt water streaming off him. Misty rain drifted down from the hills. It was as cool as Taltid had been sweltering.

Flashing dark browns and reds, colours he could not interpret, Gyrull settled beside him. He expected her to abuse him for his stupidity, but she bowed her head, displaying camouflage colours.

'I beg your indulgence. Tetrarch Gilhaelith,' she said hoarsely, inclining her head towards him. You startled me, but that is no excuse. The conveying code is a sacred one and I should not have dropped you under any circumstances What was it you wished to say to me?'

Gilhaelith lay on the wet rock, so frightened and dazed that he failed to capitalise on the advantage. A matter of the greatest moment, and great urgency too. It concerns the Snizort node that exploded and died to nothing.'

She tipped her head to one side, studying him with eyes like liquid gold. Her breast was heaving. 'Go on, pray.'

He pressed his fingers against the throbbing punctures between his ribs, praying her claws were clean. 'My knowledge of geomancy, and my studies of many nodes, tell me that a node cannot simply explode and disappear.' He explained how he came to know that. 'There must be some residue left behind to balance what has been lost. That residue, in the wrong hands, could be perilous indeed.'

'Present your reasoning, if you please, Tetrarch.'

Before he was finished, he saw, from the look in her eyes and the patterning of her skin, that she had reached the same conclusion. He had forgotten what a frightening intellect she had. Indeed, because the lyrinx ate human flesh and mostly fought with their bare hands, it was easy to underestimate them, to think of them as savages. That could be a fatal mistake.

'This residue,' said Gyrull, 'could be a mighty power, in the hands of someone who knows how to use it.'

'That is my belief,' said Gilhaelith.

'And you want it for yourself, of course.'

'I don't,' he said untruthfully, 'for I've never sought power over others. Knowledge and understanding are my passions. I would, however, like the opportunity to learn from this residue.'

'Then why tell me?'

'As a token of good faith, to set against my debt.'

Again that sideways, birdlike glance. 'You hope I'll gain for you what you can't get by yourself. And when the debt is repaid, what do you ask of me, Tetrarch?'

'My freedom. And carriage to a place where I may continue my work.'

'We'll see about that after my searchers return.'

Calling her lieutenants together, Gyrull spoke rapidly in a low voice. For once she displayed no skin-speech at all, and the others little more than blushes of yellow or grey. After a few minutes, three of the strongest lifted off from the platform and headed back across the sea, in the direction of Snizort.

'They go to establish the truth of what you've told us,' she said. 'We'll rest for an hour, then take you to Oellyll.'

'What's Oellyll?' said Gilhaelith.

'A city of ours, the best part of a day's flight from here.'

He felt the familiar panicky tightness in his chest, the difficulty of getting enough air. Once she had him there, it was unlikely she would ever let him go. And, held like a pet in a cage, subject to Gyrull's whims, he must eventually go mad.

After flying through dense cloud that night and all the next day, they arrived at Oellyll on a dark and rainy evening. Gilhaelith had no idea where in Meldorin they were. He was carried blind-folded through caverns lined with cut slabs of carven stone, into a deeper underground that the lyrinx had excavated out of rock. It was warm here, which was pleasant, for he was still saturated with an inner chill.

He learned nothing about Oellyll that night, save that it was ventilated by great bellows up on the surface. Several times he passed through their blasts of air, so strong that they almost tore him from the lyrinx's grasp. He was left in a warm room on a low platform which passed for a bed. It had an open doorway. They had no fear of him escaping for he could not stand up.

He lay on the platform, closed his eyes and did not wake for twenty-four hours, not even while their healers attended his injuries.

Two more days Gilhaelith spent in his room, lying on the platform without strength to raise his head. He had been badly hurt by immersion in the tat His liver troubled him, his head still throbbed, his heart would race for no particular reason and he felt incredibly weak. Walking the few hundred steps to the privy was beyond him. And the movement of those gallstone fragments along his internal ducts proved more excruciating than his most dismal imaginings.

Making matters worse, the food they gave him was a murky sludge the colour of rotting leaves. Reaching over the side of the platform, Gilhaelith dipped a finger in the bowl. The stuff turned out to be vegetable in origin, but quite bland. He pushed it away. The only vegetables he cared for were strongly flavoured ones, such as onions, turnips and radishes. He'd lived on a diet of slugs, pickled organs and other delicacies most of his adult life, and his palate craved exotic and the intense tastes. But if this pulverised goop was all he was going to get, he'd better eat it. He extended bony fingers, scooped up a gob of the green-brown muck, and swallowed. The repulsive blandness reminded him of his miserable childhood and the repressed memories exploded.

An orphan who had been dragged screaming out of his mother's lifeless body, he'd been carried to a far-off land by his loyal nurse, travelling by night and hiding by day. Gilhaelith had never learned why, or who he was, and had long since decided that he did not want to know. It could only cause him more trouble.

He'd never fitted in. Gilhaelith shivered as the distant memories ebbed and flowed. He'd been plagued by illness and stomach upsets as an infant. As a child, learning had been difficult, and if not for the patience of his nurse he'd still be illiterate. Once he'd mastered reading, though, and especially numbers, the whole world had opened up to him.

Then came the greatest tragedy of his life. His nurse fell ill and died, and Gilhaelith ended up in an orphans' home, fed on tasteless gruel and little enough of it. He thrust the bowl away so roughly that mush slopped all over the floor. In the home his stomach had begun to trouble him again and it wasn't until he began to feed on slugs, grubs, fish organs and other exotica that it had settled down.

Gilhaelith had been out of harmony with the world and had to fight it every step of the way, though the world showed him only brutality or indifference. Always an outsider, his feeding habits made him an object of derision and disgust. He was ostracised and bullied, and the only way he could cope was with absolute self-control. Forced to master his feelings and emotions, he had gradually extended that control to everyone around him, and then to everything.

Once grown to manhood, that iron control had helped him to accumulate great wealth, which allowed him to retreat to a place he could control completely. He'd built Nyriandiol so as to be master of his own environment, though he'd discovered that, without perfect understanding of the world, he could never have complete control. Gilhaelith, a man determined to overcome all obstacles, had set out to do just that. And first he had to discover why the world was the way it was. His life's work was born.

He'd become a geomancer and, after a century and more of study, the greatest geomancer of all, but his goal seemed as far off as ever. He still felt threatened - some unpredictable event might still overturn his carefully constructed existence. Then it had: Tiaan had appeared, and her amplimet had opened up all sorts of previously inconceivable possibilities.

But Tiaan had upset his control mechanisms. At first, because of his attraction to her, he'd found that exhilarating. Soon, however, his carefully structured life had fallen into chaos, which he'd found increasingly difficult to handle. Vithis had come, and Klarm. His servants had begun to plot behind his back. Then Gyrull had abducted him and Gilhaelith's hard-won control began to falter. He'd felt like an orphan again. In Snizort he'd allowed his relationship with Tiaan to founder. Gilhaelith regretted it, both for the loss of her friendship, and the loss of an apprentice worthy of him, but at the time there'd been little choice.

Since being trapped in the tar his life had careered out of control. His health grew worse each day, he felt ever more stressed and panicky and there were signs of breakdown that he could not admit to himself. He'd never thought he could be so vulnerable. The panic exploded, choking him.

In an effort to calm himself, he began to recite a list of minerals and their properties. He'd previously found rote exercise to be soothing in times of stress. He'd listed all the properties of quartz and fluorspar and was about to begin on calcite when his mind went completely and unaccountably blank.

Calcite, he thought. Rhombohedral crystals, sometimes prismatic or .., or ... Nothing! He could not recall any of the dozens of properties on the list, not even the variety of its colours, only that calcite was mostly white.

He picked another mineral at random, barite. Nothing. Dolomite. Nothing. Sulphur. Nothing. Then, with a horror that could not be described, the entire catalogue of minerals faded from his mind. He'd known the list by heart for a hundred and thirty years, and in that time had never forgotten the smallest detail.

It's just exhaustion, he told himself. You're pushing too hard. Give yourself a chance to recover. He put the failure out of mind, or at least tried to, but the appalling thought kept returning. He hadn't been pushing at all - the recitation had been meant to be a comfort. And from there, only one conclusion was possible. During the escape from Snizort he must have damaged a part of his brain.

Gilhaelith did not try again; he was too afraid. In his long, long life there had been few problems he'd not been able to solve by intellect, geomancy or sheer will. He'd even found a solution to the vexation of human relations - he controlled everyone who came into his life. Those who could not be controlled he simply pushed away. Until Tiaan appeared, emotion had played no part in his existence, or so he liked to think. He was a man governed by pure reason, and if his intellect deserted him, what would he have left?

After a few more days' rest he was mobile again. Gilhaelith was tracing out the familiar journey to the privy for the third time in a few hours, hobbling like an old man, when a lyrinx fell in beside him.

'Would you come this way, please?' she said politely. 'The matriarch wishes to speak with you.'

Her tone gave no indication as to whether Gyrull was pleased or otherwise. He shuffled after her, unable to raise much interest either way. His illness preoccupied him all his waking hours. He had begun to wonder if he would ever recover.

Gyrull was standing at a stone table, an oval slab that rose from the floor on a tapered stalk carved out of the native shale. She was studying a collection of papers but put them aside as he entered.

'My people have come back from Snizort,' she said. 'You were right. There was a residue left behind by the failure of the node.'

'Did they recover it?'

'Unfortunately someone found it first.'

'Who was it?' said Gilhaelith. 'One of the scrutators?'

'It would appear so.'

His idea about the residue at the node-drainer had been an inspired guess. Now that it had been confirmed, Gilhaelith was furiously thinking through the implications. Could the residue have had anything to do with Tiaan's amplimet, its communication with the node and those strange threads it had drawn throughout Snizort? Or had so much power been taken from the node that it had been unable to sustain itself and had collapsed into nothingness - nihilium? Much depended on the answer. And how might it impinge on his life's work, to understand the workings of the world, and control them?

'This residue may give humanity additional confidence,' Gyrull added. 'But then, knowing they have it will benefit us, in a way . . .'

'How so?' said Gilhaelith.

'Despite their near-defeat at Snizort, the human army is pursuing our Land forces towards the sea. We'll prepare a trap and wipe then out. What do you think of that, Tetrarch?'

'I would be sorry to meat an army' he said, 'whether human or lyrinx.'

'I regret the necessity, but we did not start this war, despite the propaganda of the scrutators. In the early days they rejected every peaceful overture we made. They regard us as abominations, even denying our right to exist. Now that we have the upper hand, and may soon win the war, I won't let the fate of their soldiers stand in the way.'

Gilhaelith was still thinking about the residue. 'SoJ was right about the node.'

'And I keep my bargains. I'll take you wherever you wish, within reason. I can't carry you far into Lauralin, nor to any place that would endanger my own life. Where do you wish to go?'

'I'm not sure,' he said. 'Because of. . .'

'Your betrayal of the scrutators,' she said helpfully. 'And the Aachim.'

He felt a momentary embarrassment. 'Quite. There are few places in Lauralin where I can live in safety now, unless I dwell in a cave as a hermit. I can't do that - my work is everything to me.' It had been and still was, though the earlier failure had shaken his confidence . ..

Gilhaelith realised that the matriarch was staring at him. 'I must have my geomantic instruments and be near a node,' he went on, 'preferably a powerful one. I'd prepared a refuge in the far south, but my health isn't good enough to go that far, without servants and loyal guards. Because of my, er, situation, suitable ones may be impossible to find. But. . .'

'Yes?' she said.

'Were you to give me a safe conduct, and a small number of your human prisoners to provide for my necessities, there's a place in Meldorin which would serve equally well. It's filled with ancient resonances and I could continue my work there.'

'You want me to provide you with servants?' she exclaimed.

'Now you're asking for more than the bargain. Should I agree, what can you offer in return?'

'My aid with problems you may encounter, of a geomantic nature,' said Gilhaelith.

'What makes you think I'm likely to encounter any?'

'I believe you will, as the war progresses. I imagine you may want to further develop your node-drainers, for example.'

'How can I trust a man who has betrayed his own kind in favour of an alien race?' Gyrull said reasonably.

'I'm descended from several human species, not just old humankind, so I don't consider I've betrayed anyone. Besides, you lyrinx are not as alien as you appear. And has not my word always been good?'

'Not always,' she said, 'since you make such a point of it. But it's enough, for the moment. You can't cause too much trouble in Meldorin, I think. Tell me - what is this place you want to go to, filled with ancient resonances?'

'It was called Alcifer, long ago.'

'Alcifer!' Slivers of yellow shone out on her flanks. 'Is that the limit of your needs, or do you demand yet more?'

Her reaction bothered him. 'It can't be more than a few days' flight from here. It was the great city built by Rulke the Charon -'

'Oh, I know all about Alcifer.' Gyrull began to laugh. Lyrinx rarely displayed amusement, but this became a great, sidesplitting guffaw that showed all her hundreds of teeth and made her sides heave like the bellows upstairs. 'Alcifer!'

'Is there some problem?' he said, anxious now. 'You did agree to do this for me . . .'

'I'm pleased to be able to repay you so easily,' she chuckled 'You could walk there from here. Oellyll is delved into the rock directly beneath Alcifer.'

Eighteen.

Ullii was sitting on a rock a pebble's throw away, Staring at Nish, as she had done all morning. She expected something of him and he had disappointed her. What could she want? He liked Ullii and cared about her, but did she really expect him to pick up from where they'd left off, months ago, as though nothing had happened since? It seemed she did her nature was single-minded, obsessional. Nish could not reciprocate, for his life had been turned inside out and he could not make sense of it. He wished Irisis were here - she understood such things instinctively.

'Let's get moving,' said Flydd.

Nish brushed away the few tracks they had left on the stony ground. Flydd rubbed crushed mustard-bush leaves over their boots and they set off to the north, taking advantage of the cover afforded by vegetation along dry creek beds. It was midday and a sweltering northerly blew in their faces. Nish, who came from a cold and drizzly land, had never experienced such heat. Green, iridescent flies hung about their eyes, noses and mouths, not to mention their wounds and whip marks, and no amount of arm-waving could get rid of them.

'I've swallowed enough flies to make a hearty meal,' he grumbled as they took a hasty break in the early afternoon. 'Where do they come from?' They were sitting under an arch of grey rock, its roof toothed like the mouth of a shark.

'Good eating for maggots, over on the battlefield,' Flydd grunted.

'Can't say the same for us.' Nish was chewing on the stem of a piece of dry grass. It generated a little moisture, which only reminded him how hungry he was. And his boot was coming apart again. He looped another lace through it, knowing it would soon wear through like the others.

Pull your belt in another notch.'

'If I do it'll cut me in half.'

'At least it'll be an end to your infernal griping.'

Nish didn't react - Flydd's carping was almost affectionate these days.

'I'm thirsty,' said Ullii plaintively.

'We'll get water down in that gully, Ullii,' Flydd said. 'It won't be long now.' He treated her far more gently than he did Nish. But then, Ullii never did anything wrong.

The baked earth crunched underfoot as they went out into the sun again. It seemed to grow hotter, and the flies more numerous, with every step. For some reason that Nish could not fathom, they swarmed around Ullii. The little seeker plodded on, not complaining, but in misery.

'Stop for a moment, Ullii.' Flydd tore the bottom off her green smock, knotted the corners into a bag and dropped it over her head. Ullii didn't need to see where she was going.

Several times they saw air-floaters behind them but all were moving around the army camps, or following the lines of clankers being dragged to the north-west. Late in the afternoon, however, one appeared close to the node crater, now two leagues distant. The machine circled it several times, floated upwards, then turned directly towards them.

They were scrambling along the rim of an undulating plateau which afforded a good view but little cover, just scattered mounds of orange boulders, sparse, scrubby undergrowth and occasional small trees twisted into bizarre shapes by the wind. Some distance to their left, a deep ravine cut through a corner of the plateau.

'I don't like it,' said Flydd. The air-floater seemed to be following every twist and turn of their path, as if they had left a trail on the ground. 'How can it track us from that height?'

'What if we were to slip into the ravine?' said Nish.