Kettle moved through the town wrapped in a cocoon of shadow. In an hour the great red eye of the sun would see the carnage for itself but no other witness remained to watch it roll back the night. The fires had burned out, the smoke stripped away by the wind, but the stink of burning remained. The stink and the dead and the ruins of their homes.

The Scithrowl had spared none. They left the corpses of their own scattered infrequently here and there among the bodies of farmers, weavers, shepherds, and of children who might one day have taken up those trades. A small blonde girl lay broken in the doorway to an unburned hut, her hair straw and mud. A woman nearby curled around the wound that had killed her. The mud showed how far she had dragged herself to reach her daughter but she had died three yards short of touching her child that last time.

In the harbour a single boat still burned amid the blackened and half-sunken wrecks. From behind Kettle’s eyes Nona wondered what its cargo was that it should sustain a flame when all else had long since guttered into darkness. She knew that Kettle had drawn her sleeping mind along their thread-bond to show her something. Too often lately Nona had rolled yawning from her bed after first waking in the small hours to find herself inhabiting Kettle as the Grey Sister stalked her prey. Last time it had been a Scithrowl commander amid his army of five hundred soldiers. Kettle had ghosted among the lesser tents and cut her way into the grand pavilion in which the officer slept beneath hoola furs. Nona could make no sense of it: signposting their leaders with such luxury. The empire generals slept in tents identical to the common soldiers to foil just such assassination attempts.

Kettle turned from the dark lake and moved on through the town towards its margins. She had something to show Nona. She rarely spoke on these tutorials, needing all her focus to keep her alive. Even here Scithrowl softmen might be lurking, ready to kill or capture scouts, or Noi-Guin assassins, loyal to neither side, only to the coin that paid their fee.

Ahead of them loomed a larger building, no detail hidden from Kettle’s dark-sight. A stone construction, the roof gone, presumably taken by flames, though the stink of burning hung less heavily here. Kettle closed the distance. Gravemarkers stood behind the building. Dozens of them. A church then. Kettle glanced skywards to where the Hope burned white amid the crimson scattered heavens. A Hope church then, roofless by design so that the white light could reach in and wash away all sin.

And suddenly, as Kettle approached the shattered doors, Nona knew where she was. White Lake, not eighty miles from the walls of Verity. White Lake, where her mother lay beneath the ground and doubtless now Preacher Mickel lay sprawled upon it. Adoma had splinter armies pillaging just five days’ march from the capital. Swift horses could bring them to the foot of the Rock of Faith in less than half that time.

Something caught Kettle’s eye. Something Nona had missed. Kettle pressed herself to the church wall, pulling darkness to herself as if drawing a breath. The night entered her as ink soaks into blotting paper. There, out across the graveyard, a pale, questing tentacle, almost flat to the ground, insubstantial as mist. Another, yards long, snaking out between the graves. A pain spider, some creature of the softmen in service to the Scithrowl Battle-Queen Adoma. Rumour had it that they bred such monstrosities, releasing demons from the black ice into unholy alliance with flesh.

More tentacles insinuated themselves across the barren ground, one thin as leather and broad as a hand sliding noiselessly over the top of the church wall just yards from Kettle’s head. Even at that distance her skin sang with echoes of the agony its touch would bring.

Nona woke sweat-soaked and alone, her body hunched, arms tight around her. She lay in the darkness of the Holy Class dormitory trying to still a racing heart. Kettle had kicked her out, requiring her whole concentration.

Sleep did not return that night. They were coming to the sharp end of things. The peace of the convent, seemingly eternal, would not last. Idle days, bickering among friends, the rivalries of children, all of it was passing into memory. A black tide was coming from the east and all the empire hadn’t the strength to stand before it.

‘We don’t even know the book exists. It’s not as if the high priest posts a list of forbidden books on his door.’ Ara stood with Jula and Nona in the lee of the Dome of the Ancestor, watching Path Tower, a dark finger of stone.

‘The Inquisition burned my History of Saint Devid,’ Nona said.

‘It wasn’t yours, and Kettle shouldn’t have allowed it in the scriptorium library,’ Jula said primly. ‘And that was a banned book, not a forbidden one. Banned books are burned, forbidden ones are just … forbidden.’

‘So how come Sister Pan has one, if it even exists?’ Ara asked.

‘We know it exists because there are references to it that they forgot to remove from other books by Aquinas. And we know that Sister Pan has a copy because she quotes from it when talking about the lost cities.’

‘You haven’t read it! How do you know she’s quoting from it?’ Ara rolled her eyes.

‘Aquinas has a very distinctive prose style.’ Jula folded her arms.

‘That’s it? We’re breaking into Sister Pan’s secret room based on distinctive prose style?’ Ara asked.

‘How do you know she hasn’t memorized the quotes?’ Nona demanded.

‘She still calls you Nina sometimes.’ Jula grinned.

‘Fair point.’ Nona nodded slowly. ‘So I just have to get into the Third Room …’

‘Or I do,’ Ara said.

‘Do you know how?’ Nona asked.

‘No, but you don’t either.’

Nona started towards the tower. ‘We’ll both try, then.’

Nona narrowed her eyes at Path Tower, black against the wash of the sky. Sister Rule taught that it was the oldest building on the Rock of Faith, predating the convent by centuries. Given that all save the top and bottommost rooms lacked doors or windows, Nona supposed it had been built for a powerful Path-mage though no records remained to name the first occupant. She approached the east entrance, apprehension rising. It wasn’t as if they were about to attempt the impossible. Every novice with ambitions to be a Mystic Sister had to enter the Third Room unaided. It was part of the Path-test. Maybe all of it. Nona would choose the red habit, not the sky colours of the Mystics, but she wanted to pass the Path-test even so.

Ruli followed Nona in through the east door, Ara entered by the north. They met at the bottom of the stairs in the room of portraits. Two dozen or more Mystic Sisters regarded them from wooden frames. Each woman was pictured amid abstract representations of their magic, the variety remarkable. Nona’s favourite was a young red-headed Holy Witch whose hair became flames. When you looked closer at her you could see that in the darkness of each pupil a tiny star burned crimson.

‘We know two things,’ Nona said as Ara joined them.

‘What?’

‘Firstly it’s all about Path. Otherwise Joeli would have cracked it months ago.’ Ara and Nona had been waiting an age for the individual training Sister Pan gave candidates for the Path-test. The old woman liked to instruct one novice at a time and whatever lessons she had been trying to teach hadn’t been getting through Joeli’s skull. ‘Joeli Namsis couldn’t take two steps on the Path if you threw her at it.’