Nona bit down on Ruli’s pain and spoke into her mind.

I can save you. I’m going to try the doors but if I can’t get through I’ll need to take control of your body. You really have to trust me for that to happen.

Ruli made no attempt to hide her relief. You can do the hurting and I’ll sit back and watch you kill this bitch. But even if you take over you’ll still be me … and I’m a bit tied up.

That’s why I want to try the doors first. Stay strong.

Hurry, Nona! He’s getting his knife out … and that’s supposed to be easy compared to what Safira is going to do to me! I’m not strong like you …

Nona returned to her flesh with a shuddering breath. She turned her stare towards the blank wall ending the corridor, reaching out with her rock-work. It didn’t require much skill to understand the nature of the barrier. Even from fifty yards away she knew. The corridor had been sealed with a slab of iron two feet thick.

Nona paused, considering her options. From Kettle’s thread-bond a pulsing mix of grief, anger, and fear nagged at her heightened senses along with the rush of combat. The pain from Ruli’s beating still throbbed at the end of her thread-bond, but the rising terror of the approaching knife eclipsed it. Nona steeled herself to join her friend, but even as she gathered herself something far stronger than fear or rage hammered through her. It came from the bond she had with Ara. The bond that had registered nothing but a sullen silence since Nona left the Rock of Faith. Now suddenly it echoed with Ara’s first step upon the Path and the reverberation rang through her louder than any bell.

By the time Nona had pushed her way into Ara’s mind her friend had dropped from the Path into a fight so one-sided it made the defence outside Crucical’s palace look like a meeting of equals. Ara fought alone amid the forest of pillars against not scores but hundreds of Pelarthi mercenaries.

Lano Tacsis was behind this. Sherzal had said so. His coin had brought the Pelarthi from the ice margins. Abbess Wheel had said that the high priest had ordered that Nona be the one to stay. Tacsis gold and Tacsis influence had steered High Priest Nevis’s hand to set Nona alone before the convent and its shipheart. Only the long reach of Abbess Glass had enabled her to step clear. Nona remembered the promise she had made to a dying woman. The promise that she would choose neither Red nor Grey nor the sky-blue of the Mystic Sister but instead take the black of a Holy Sister. Even on her deathbed Glass had seen who would replace her as abbess and how much favour such a gesture would win from her. Without that goodwill it would be Nona at the convent miles from the shipheart, unable to work any of the wonders she had been working along her thread-bond and those she still planned to work.

Nona crouched, pinned by indecision. She felt Abbess Glass’s hand upon her shoulder but found no sense of direction in it. Even the old woman’s legendary foresight had its limits. She could not have seen this end. It fell to Nona now and she felt unequal to the challenge. Ruli’s terror and pain began to spike along their thread-bond. Kettle’s despairing exhaustion reached out to Nona through the bond they shared. Five miles away another friend released the awesome power of the Path in her single-handed attempt to destroy an army that had been sent to kill not Sister Thorn but Sister Cage.

Nona couldn’t lose Ara. Not her. With a cry of despair Nona threw herself across the corridor, scooped up the shipheart, and ran into the darkened room to her left. The shipheart’s glow revealed what Ruli had glimpsed on her way past, what Zole had spoken of back in the black ice. A huge ring, too large to have come into the small room through the single doorway. It leaned against the rear wall, too tall to stand vertical. Its dimensions and markings were identical to those on the ring that Zole had sent Nona through against her will three years earlier. Without pausing to think Nona leapt into the circle. She held the shipheart out before her, and every fibre of her being tensed for collision with the wall behind the ring.

The cave into which Nona stumbled was too big for the shipheart’s light to find its sides. Behind her a ring of strangely crystalline metal rocked gently on its edge. The glow was already dying from the scores of symbols around its perimeter. On the floor for yards in all directions lay fragments of the flowstone that had once coated the ring. The pieces lay in the same broken chaos in which they had landed when Nona had emerged here three years earlier. That time she had travelled far more than five miles. Zole had flung her a hundred times further from another of the ring’s counterparts beneath the black ice.

Nona had discovered this ring with Ara and the others in her early exploration of the undercaves. A holothaur had guarded it using nothing but terror. Those days seemed long ago and simpler. Part of Nona wished the ancient magic could send her back across the years as easily as across miles.

For a moment, as the light died from the great circle, the shipheart flared. Cavern walls appeared, described in violet and black, a roof above, hung with a downward-questing forest of stalactites. Pools patterned the undulating floor, each surface still trembling with the shock of Nona’s arrival. Nona’s senses flared too. The world of threads, in which humanity’s paper-thin reality hung, lay stripped bare before her eyes. Her rock-sense ran wild, reaching out through the void-riddled vastness of the Rock of Faith, echoing down passages unknown to man, stealing along secret ways, lacing around the sleeping mass of the Glasswater, the weight of its countless gallons held back behind such a thinness of stone …

Nona shook away the sensations and wasted no time. She ran, following paths that she and her friends had explored years earlier. It took no more than a couple of minutes to reach the passage where once she had struggled to climb a fissure to reach the scene of Hessa’s murder.

Nona leapt towards the opening overhead and within three heartbeats was pulling herself out of the fissure’s mouth into the space before the shipheart’s old vault, the place from which Yisht had once stolen it.

‘Lano wants you.’ Nona spoke to the shipheart. ‘He will not have you.’ She pushed the sphere against the smooth wall of the passage and exerted her power over the rock. Moments later she withdrew her hand. The shipheart remained, entombed behind inches of stone with few signs of disturbance to betray its presence.

The voices of her devils called at her in the silence that remained now that the hurricane of the shipheart’s power no longer blew through her. They told her to run. To take the shipheart and escape through the ring to some distant place. They whispered that Ara was false, a child of the Sis, raised on gold. They told her that Ara had always seen her as a peasant, never as a true friend. They told her that Ara would never love her in return. They told her that in her place Ara would run.

And Nona believed them.

‘It doesn’t matter.’ She stumbled on along the tunnel, away from the shipheart. With her mind splintering, her thoughts drawn one way then the other, Nona clung to the simplest of her truths. Those she first found. ‘It doesn’t matter what she thinks of me. It doesn’t matter if she hates me. She’s my friend. I won’t leave her.’

She ran on blind, following her memory of the place, trailing a hand against the wall, falling, rising, crawling, wriggling, reaching Apple’s caves. The gate to the Shade steps surrendered to a slash of her blades and she emerged to run through the convent where she had grown from a small child into the young woman Abbess Glass had burdened with too much trust.