All too soon, Nish pulled Tiaan to her feet. She let out a faint cry as the rope tore her wrist. He only jerked it harder. Tears formed on Tiaan’s lashes as she stumbled after him. She blinked them away.

‘You are cruel, Nish,’ said the small woman.

‘No more than she deserves!’ he snapped, and kept going.

Ullii stopped dead, crouched and slowly began to curl up, covering her face with her arms. Nish was slow to realise that she was not following. ‘Ullii?’ he said, looking around.

There was no reply. Tiaan expected Nish to fly into a rage but he hurried back, dragging her by the rope, and fell to his knees beside Ullii. ‘I’m sorry,’ he said softly. ‘I’m really sorry.’

Ullii remained curled into a tiny ball. Nish took off his pack and Tiaan was amazed at the change in him. She had always thought him a lecher and a layabout, and today, a monster; but he genuinely cared for Ullii.

‘It’s nine in the morning. We’ll camp until four.’ He tossed his cloak at Tiaan’s feet.

She rested on it. It was cool on this level, though not unpleasantly so. Tiaan was desperately tired but there was too much in her mind for her to sleep. The past day contained a lifetime of trauma and tragedy. Minis’s betrayal, and the Aachim’s treachery from the very beginning, she could not deal with.

Haani’s broken body still lay beside the shaft, abandoned. I promised that I would never leave you, but I was too afraid, Haani. I had the chance to do the honourable thing. If only …

The day passed. Tiaan dozed but woke as tired as before and aching in every muscle. Ullii had not forgiven Nish. She did not even look in his direction when he spoke to her.

They ate in silence. Nish tied Tiaan’s rope to the stair and disappeared with the water bottles. Ullii squatted, watching with her masked eyes. Tiaan did not think the seeker was doing sentry duty. What would Ullii do if she tried to escape? Tiaan did not attempt it. No doubt Nish was not far away.

After he returned, Ullii gave Tiaan a generous swig from her bottle. They headed off, Nish leading, Tiaan stumbling at the end of the rope, Ullii padding behind her. Tiaan closed her eyes. This was worse than anything she had endured in the breeding factory; worse than being held captive by the lyrinx and forced to aid them in their ghastly flesh-forming.

She sank into a dazed daydream. Tiaan had always been a dreamer, her escape from a miserable childhood in the clanker manufactory. Her daydreams arose from romantic tales her beloved grandmother had told her.

She conjured up the image of her mother’s mother. Tiaan thought, and remembered, in pictures, so Grandma Aaloe’s face was as clear as if she was walking beside her. A small woman, almost as wide as she was high, Aaloe had a face as round as the moon and an embrace like a warm pillow. Her man had been killed in the war when Aaloe was nineteen and Tiaan’s mother, Marnie, had just conceived. Aaloe had not partnered again but her tales were full of handsome young men rescuing beautiful maidens, or as often, maidens going to the aid of lost lovers.

Minis had been Tiaan’s personal dream, but within minutes of meeting him that had been destroyed. She hated him for his treachery, but despised him for being so weak. He had said he loved her, but could not stand up to Vithis. Vithis ordered Minis to repudiate Tiaan. And Minis had.

‘Get a move on, artisan!’

Nish jerked the rope so hard that she fell to one skinned knee. She gave him a hate-filled glare. His returning smile reminded her of a jackal.

It had been her dreams, and her longings, that had got her into this trouble in the first place. All her life she had been a misfit. Everyone was required to mate but, being so shy, she had found one excuse after another to avoid that duty. Why could she not have settled down at the manufactory like the other artisans, taken the best partner she could find, produced the required number of children, and worked hard at the craft she had come to love?

The evening dragged on. They made slow progress, the thin air barely enough to sustain them. No one knew where to go. Nish had tried countless ways but all doubled back on themselves as if enchanted.

Long after midnight they stopped for dinner and a nap, after which Tiaan’s hands were untied and she was permitted to go into one of the bathing rooms to relieve herself. As he followed, she snapped, ‘Still a little pervert, Nish?’

He went scarlet. ‘Go with her, Ullii,’ Nish said coldly. ‘Don’t take your eyes off the traitor.’

Obediently, Ullii followed Tiaan into the room but took no further notice of her. Ullii wandered about, touching everything with her fingertips. She pulled down a lever and water gushed from a device like an upside-down funnel. The small woman jumped, began to curl up, then unfolded with all the grace of a ballet dancer. Creeping back to the tap, she wiggled her fingers under the flow, entranced.

Tiaan slipped around the corner to a washing trough, beyond which she spied another door. Could it be this easy? Ullii was paying her no attention. Edging it open, Tiaan found herself in a set of chambers like many she had seen in Tirthrax. She went through the bedchamber, out the far door and tiptoed around a gentle curve. Passages led three ways. Straight ahead lay a stair entirely made of glass. More extravagant than any she had looked at so far, it looped back and forth across the room like the flourishes on the end of a queen’s signature. She would be seen on it from top to bottom. But it led up, and that felt right.

As Tiaan reached the first loop of the stair she heard Nish’s bellow of rage. She bolted.

‘There she is!’ He took the glass treads three at a time, shaking the stair with every step.

She fled up and up. Nish gained slowly. At the top she encountered another stair, made of obsidian, then a third, a simple spiral barely wider than her hips. It was so steep that to look down caused sickening lurches in her stomach.

Light appeared above her. Daylight – a way out. She hauled herself up by her arms. A cavern opened out before her, a hemisphere scooped from the native rock of the mountain. The floor, walls and roof were like polished granite, the flat side a single sheet of glass five spans high. Outside lay a platform with a high-backed stone seat, and beyond that a sea of peaks and snow and ice went all the way to infinity. The sun was rising.

Tiaan ran up to the glass and stopped. It was inset into the stone on all sides. She pressed her hands against it but had to snatch them away – the glass was bitterly cold. If there was a door she could see no sign of it, nor any other way out. Putting her back to the glass, she waited. Nish was scarlet in the face, his step as unsteady as hers, but he drove himself on.

‘Don’t move!’ He lashed at her with the rope. One end caught her on the cheek. She cried out, he jerked her to him and swiftly bound her hands.

‘Call me what you like,’ he gritted, ‘I’ll not untie you again until we stand inside the gates of the manufactory.’

Ullii came creeping up the steps. After slowly circumnavigating the room, she looked out through the glass with her masked eyes.

When Tiaan was so bound that she could move neither hands nor arms, Nish ran a length of rope from her to him. ‘Go down!’ he croaked, harsh as a raven.

Dead inside, Tiaan obeyed. Should she take the first opportunity to fall and carry him with her? She had just set her foot on the top step when, with a whirr, the glass wall slid into the stone.

Nish spun around. ‘What’s that, Ullii?’

‘I can see the Art,’ Ullii said softly.

Someone rose from the seat. The figure turned, tossing back her hood. As she approached, the sun caught her hair, illuminating a few flame-red strands among the grey. Her hands were bare, the fingers remarkably long, almost twice the length of her palm. Aachim! Chills fizzed up and down Tiaan’s backbone.