Tiaan lost focus. With the mad shrieking in her head, and Ryll’s cries and thrashing before her, she could not visualise the source.

Her eyes sprang open. Ryll’s hand lost its grip on the nylatl and fell smack against the floor. The creature dug in its claws. One spine had pierced his scalp and was going up and down, trying to penetrate his skull. The nylatl’s skin was striped in brilliant reds, yellows and blacks, like a poisonous caterpillar. Ryll flashed in delirious, psychedelic colours.

She could not waste a second. Tiaan found that hexagonal column again and suddenly she knew how to use it. The Principle of Similarity, one of the vital principles used by artisans, was the perfect choice here, for the rock column had the same shape as the amplimet. Power cascaded from the field into the crystal and she hurled it at the crack.

It parted. Friction held the column for a moment, and then it fell. She drew power from its motion, just a trickle at first but increasing as it accelerated into the magma chamber.

The bead of light in her amplimet swelled. A focussed beam burst forth. She directed it onto the nylatl. It was not bright enough to hurt it. Not yet. The nylatl arched its back. Ryll kicked weakly. The beam slipped off the creature.

‘Don’t move, Ryll!’ She hoped his hearing had not closed down. Her head felt eaten away inside. The nylatl began to struggle desperately.

In her mind’s eye Tiaan could see the column falling as if she was watching it in slow motion. It accelerated toward that glowing pool of magma.

Her head felt as hot as that magma; white heat licked down her backbone; every nerve fibre in her body was ablaze. Her senses were shutting down one by one. She could no longer feel her feet on the floor. The hot carrion smell of the nylatl vanished. Ryll’s agonised wails cut off. The shrieking chuckle of the creature faded away.

Her sight began to break up at the edges; her eyes felt full of pinpricks. Tiaan clung grimly to sight; she must be able to see to aim. The last she saw, as her vision was going completely, was the nylatl arching up on Ryll’s head, preparing to hurl itself at the real enemy – her!

The black column plunged into the pool, giving up its energy in a burst that blacked Tiaan out. She did not see the brilliant purple light that burst, fan-like, from the amplimet. She tracked the creature’s leap through the field. Just the edge of the fan caught the nylatl, burning the ends off its spines and heating its skin to blister point. Its overheated muscles spasmed, hurling it against the wall so hard that it was knocked senseless.

She did not see the central pulse heat the wall to white-hot, until the metal ran down and puddled on the sloping floor. With an explosion of sparks the light burst through, carving a ragged hole to the outside. Tiaan saw and felt nothing. She lay senseless. The amplimet went out.

There were shouts outside, the lock was forced and Liett scrabbled through the entrance, bent low, followed by Coeland. They stared at the destruction. A red pool of iron, large enough to fill a number of wheelbarrows, was congealing on the floor. Ash and cinders lay everywhere. The room was as hot as a sauna. Ryll crouched in a groaning, lacerated heap.

‘What happened?’ Liett shouted.

One of Ryll’s arms twitched. Liett lifted his battered head onto her knee, wiping blood out of his eyes. She stroked his dull crest. He rolled his head and his eyes lit on the nylatl, lying against the wall. It was covered in pus-coloured blisters. Smoke curled up from several of the spines. Its skin was a bilious yellow. It looked dead.

‘It tried to kill me, Liett,’ Ryll gasped. ‘Tiaan twice saved me. Is she …?’

Coeland bent over her. ‘She lives.’

Ryll’s eyes widened in terror. ‘The nylatl moved. Kill it!’

The creature shot past them, hurtled through the doorway and disappeared.

‘Sound the alarm!’ Ryll choked. ‘Find it, and destroy it!’

Coeland and Liett went after the nylatl. Ryll forced himself to his feet, glancing at Tiaan, who lay as before. He eyed the hole in the wall, saluted Tiaan with a shaky hand and went out. The door slammed. The lock clicked.

Tiaan felt her senses coming back in the same order as they had disappeared. She tasted blood from a bitten tongue. Her scalp throbbed. She smelt lyrinx blood and carrion. And something else – fresh air on her face. Cold air!

The chance had come – the only one she’d get. She did not move as the lyrinx checked her, nor even as the nylatl got away and the two went after it. Only after Ryll had gone, locking the door behind him, did she climb to her feet.

The smell of freedom made her eyes water, or maybe it was the fumes. She opened her eyes and saw nothing. Tiaan almost panicked, then the room brightened as if a lantern had been turned up and her sight was back.

There was a gaping hole in the wall, large enough to get through. She put her head out. The metal was still hot but cooling rapidly. The spire, clotted here and there with rock, was steep, though not so steep that she could not climb down.

She had to take the chance even if she was caught within minutes. Tiaan stuffed her devices into her pack and threw it over her shoulder. A bare blade lay on the bench, the one Ryll had used as a scalpel. She took that too. The amplimet was on the floor. Tiaan pressed it to her lips, gave thanks for the miracle and packed it away. Finally she put a finger in a clot of Ryll’s blood and wrote crudely on the wall, ‘Two lives! My debt is paid!’

She doubted that it would stop the lyrinx from coming after her, but Tiaan wanted it to be on the record. If she was captured she would fight them to the death. Better that than be forced to collaborate again, even for Minis.

Laying a stool across the hot aperture, she crawled out and began to pick her way down. Tiaan felt hot and cold and shivery, an inevitable result of so abusing her talent. Still, she could walk, and climb, and defend herself if she had to.

It was further than it looked, and steeper. And much, much colder. After months inside the unnatural warmth of Kalissin, Tiaan was quite unused to the winter cold. Yet even the outside of Kalissin was considerably warmer than the rest of Faralladell. It would be perishing on the other side of the lake. Out of sight of the aperture, she put on her mountain clothing.

She hoped they had not yet caught the nylatl. With luck, not that she’d had much of that lately, it might be an hour or two before they discovered she was gone. Tiaan did not build up her hopes. The chance of getting away was remote.

She tried not to think of the nylatl escaping. Tiaan could still see the look in its eyes as it prepared to abandon Ryll and leap at her. She would have no chance against it, if it got out.

Not far to the bottom now. There was little likelihood of being seen from inside, for the windows were small and it was easy to keep away from them. Tiaan squinted across the lake but the mist-wreathed water blurred into the snowy shores beyond. There was no colour in this landscape. It might have been two leagues across, or five.

It was approaching noon by the time she made it to the bottom of the spire, which rose out of a collar of angular rubble clothed in dense broad-leaved trees. They looked quite out of place here.

The ground was warm – Tiaan could feel it through the soles of her boots. The air was too, though only near the ground. The wind blowing off the lake felt dank.

She negotiated her way through shoulder-high ferns. Cushiony mosses lay underfoot and the forest had a moist organic reek she had never smelt before, though she associated it with the warm forests of the north. It was not far down to the water. When she reached it Tiaan looked back.

The sun’s slanting rays passed between the cloud layers to paint the dark spire in reds and browns. Halfway up she saw her ragged escape hole. There was no sign of pursuit. Perhaps Ryll, honourable creature that he was, considered the debt repaid. Had he given her this chance?