But then she hadn’t wanted to talk much either. Hearing Finn’s voice had been a sudden joy, but almost at once it had soured, because he had sounded so different, so full of anxiety.

I haven’t abandoned you. I think about you all the time.

Was that true? Was his new life really not the Paradise he’d expected?

In the darkness of the vault she said angrily, ‘You should have let me tell them about the Glove. The Sapient knew there was something. It might have helped...’

‘The Glove is mine. Don’t forget it.’

‘Ours.’

‘Don’t push me too far, Attia.’ He was silent a moment, then muttered, ‘Find the Warden, Jared said. Well, that’s just what we’re doing. If Finn’s failed us we have to look out for ourselves.’

‘So it wasn’t that you were scared to tell them,’ she said acidly.

His shoulders tightened. ‘No. It wasn’t. The Glove is none of Finn’s business.’

‘I thought oathbrothers shared everything.’

‘Finn has freedom. He isn’t sharing that.’ Suddenly they rode out from the archway, and the horse stopped, as if in astonishment.

In this Wing the light was a dull red. Below them was a hall larger than any Attia had ever seen, its distant floor crisscrossed by transitways and tracks. They were high in its roof, and from their feet a great curving viaduct carried the road across, so that Attia could see its arches and tapering columns disappearing into the mirk. Fires burned like tiny Eyes on the floor of the hail.

‘I’m stiff.’

‘Get down then.’ She slid from the horse and the road felt unsteady under her feet. She crossed to the rusty railing and looked over.

There were people down there, thousands of them. Great migrations of people, pushing trucks and waggons, carrying children. She saw flocks of sheep, a few goats, some precious cattle, the herders’ armour gleaming in the coppery light.

‘Look at this. Where are they all going?’

‘The opposite way to us.’ Keiro didn’t dismount. He sat tall, gazing down. ‘People are always moving in the Prison.

They always think there’s somewhere better. The next Wing, the next level. They’re fools.’ He was right. Unlike the Realm, Incarceron was always in a state of change; Wings were reabsorbed, doors and gates sealed themselves, steel bars sprang up in tunnels. But she wondered what cataclysm had caused such numbers to travel, what force drove them on. Was this the result of the dying light? The growing cold?

‘ Come on,’ Keiro said. ‘We have to cross this thing, so let’s get on with it.’ She didn’t like the idea. The viaduct was barely wide enough for a waggon. It had no parapets, just a surface potholed with rust and a gulf of air on each side. It was so high faint wisps of cloud hung unmoving across it.

‘We should lead the horse. If it panics …’ Keiro shrugged and dismounted. ‘Fine. I’ll lead, you come behind. Stay alert.’

‘No one’s going to attack us up here!’

‘That remark shows why you were a dog-slave and I was . . . almost . . . Winglord. This is a track, right?’

‘Yes . . .’

‘Then someone owns it. Someone always does. If we’re lucky there’ll be a toll to pay at the far end.’

‘And if we’re unlucky?’ He laughed, as if the danger had cheered him. ‘We make e quick descent. Though maybe not, because the Prison’s on our side now. It has reasons to keep us safe.’ Attia watched him lead the horse on to the viaduct before she said quietly, ‘Incarceron wants the Glove. I don’t suppose it cares who brings it.’ He heard her, she was sure. But he didn’t look back.

Crossing the rusting structure was precarious. The horse was nervous; it whickered and once sidestepped, and Keiro soothed it continuously in a low irritated mutter, swearwords merging seamlessly with comfort. Atha tried not to look to either side. There was a strong wind that nudged slyly against her; she braced her body, aware that with one gust Incarceron could topple her over the edge.

There was nothing to hold on to. She paced in terror, foot before foot.

The surface was corroded. Debris lay on it, scraps of metal, abandoned filth, snags of cloth caught from the wind and fluttering like ragged flags. Her feet crunched the frail bones of a bird.

She concentrated on walking, barely lifting her head. Gradually she became aware of empty space, a giddiness of air. Small dark tendrils began to sprawl across the track.

‘What’s that?’

‘Ivy.’ Keiro’s mutter was tight with tension. ‘Growing up from below.’ How could it grow this far? She glanced briefly to the right and giddiness swept her like sweat. Tiny people moved beneath, the sound of wheels and voices faint on the wind.

Her coat flapped against her.

The ivy thickened. It became a treacherous tangle of glossy leaves. In places it was impassable; Keiro had to coax the terrified horse along the very edge of the viaduct, its hooves clanging on metal. His voice was a low mutter.

‘Come on, you scrawny nag. Come on, you useless beggar.’ Then he stopped.

His voice was snatched by the wind. ‘There’s a big hole here. Be careful.’ When she came to it she saw its charred edge first, crumbling with rust. Wind howled up through it. Below, iron girders corroded, old bird’s-nests in their joists. A heavy chain looped into emptiness.

Soon there were other holes. The track became a yielding nightmare, creaking ominously wherever the horse trod.

After a few minutes, she realized Keiro had stopped.

‘Is it blocked?’

‘As good as.’ His voice was tight, oddly breathless. His breath frosted as he looked back at her, ‘We should go back.

We’ll never cross this.’

‘We’ve come too far!’

‘The horse is on the edge of panic.’ Was he scared? His voice was low, his face set. For a moment she sensed weakness, but then his hissed anger reassured her. ‘Back up, Attia!’ She turned.

And saw the impossible.

Masked figures were swarming up over the sides of the viaduct, through holes, up chains and bines of ivy. The horse gave a whinny of fear and reared. Keiro dropped the reins and leapt back.

She knew it was over. The horse plunged in terror; it would fall, and far below the starving people would butcher its body.

Then one of the masked people grabbed it, flung a cloak over its eyes and expertly led it away into the dark.

There were about ten of them. They were small and shin, and wore feathered helms, all black, except for a tagged lightning flash across the right eye. They held Keiro in a ring of aimed firelocks. But none of them came near Attia.

She stood, poised, the knife ready.

Keiro drew himself up, his blue eyes fierce. His hand dropped to his sword.

‘Don’t touch that.’ The tallest raider took the weapon, then turned to Attia. ‘Is he your slave?’ The voice was a girl’s. The eyes in the mask were mismatched — one alive and grey, the other with a pupil of gold, an unseeing stone.

At once Attia said, ‘Yes. Don’t kill him. He belongs to me.’ Keiro snorted but didn’t move. She hoped he’d have the sense to stay silent.

The masked girls — for Attia was sure they were all girls — glanced at each other. Then the leader made a sign. The firelocks were lowered.

Keiro looked at Attia. She knew what that look meant. The Glove was in the inner pocket of his coat and they’d find it if they searched him.

He folded his arms and grinned. ‘Surrounded by women.

Things are looking up.’ Attia glared. ‘Shut up. Slave.’ The golden-eyed girl circled him. ‘He doesn’t have the bearing of a slave. He is arrogant, and a man, and he thinks himself stronger than us.’ She gave a curt nod. ‘Throw him over.’

‘No!’ Attia stepped forward. ‘No. He belongs to me. Believe me, I’ll fight anyone who tries to kill him.’ The masked girl stared at Keiro. Her golden eye glittered and Attia realized that it was not blind, that she saw through it in some way. A halfwoman.