“We should separate,” Zole said. Her left hand bristled with cross-knives stolen from the dead assassin.

“We should not!” Kettle abandoned the narrow opening and moved on, veering down the smaller fork where the passage split. “You’re in my care, novice. And how would I find you again?”

“I found you before. I can do it again. I will make a diversion. You can rescue Nona.”

“This is the Tetragode, Zole! The Tetragode! You’re a novice! You shouldn’t be here! Neither should I . . .”

Kettle took a right turn down a narrow passage delving steeply into the mountain’s depths. The floor fell in uneven, muddy steps, a steady trickle of water spilling down them.

“I am the Chosen One.” Zole stopped by a fissure in the wall, a vertical slot wide enough for an arm but not a shoulder. “That is what they say. So either have faith in me, or stop worrying. If the Argatha’s prophecy is a piece of nonsense then I am just a child from the ice, of no particular value.” She reached into the crack beside her, the nitre-caked walls scraping her arm.

“You’re of particular value, chosen or not.” Kettle clasped the girl’s shoulder, knowing anything more affectionate would unsettle her.

Zole twisted her mouth into an almost-smile. Her hand was empty now, the black-skin and cross-knives stowed away. She slid deeper into the crack and laid her palm against the rock where it gripped her. “Worry about yourself, sister. And Nona.” Her brow furrowed and, with obvious effort, she pushed. And somehow the rock moved. The whole fissure widened, the wall bulging to accommodate the displaced volume, as if the whole thing were semi-liquid.

“How—”

“Yisht was my mentor.” Zole eased her way into the crack. The blood began to trickle from her left nostril again as she taxed her powers. “And there is a shipheart in this place. Can you not feel it?”

Kettle thought for a moment. She felt nothing specific, but it was true that she saw through the utter darkness of the caves with greater clarity than she had experienced before. And prior to Yisht’s theft of the Sweet Mercy’s shipheart Kettle’s shadow-working had always improved when she neared the vault in which it was kept.

“Be careful!” she called after Zole.

“They will not find me.” The fissure narrowed, rock groaning, as the novice moved from sight. “I will find them.”

“Watch for traps . . .” Kettle stared at the crack, unremarkable now, with only a handful of fractures to mark Zole’s passage. She wanted to call her back. Whatever her talents, however chosen she might be, she was still only a girl, a novice, and this was the Tetragode, a place where the most legendary of the Grey would fear to walk. Sister Cloud had done battle with Noi-Guin centuries ago and barely escaped with her life. Kettle had accepted when she understood her destination that she would not be coming back. She found it harder to accept the same for Zole or Nona.

“Ancestor watch over you.” A whisper. And with throwing stars in hand, Kettle carried on down the slippery descent.

* * *

• • •

EVER SINCE APPLE had pushed Kettle partway into the dark world to save her life Kettle had felt the shadow as something fluid, alive almost. Every shadow-worker experiences some element of that sensation but for those steeped in shadow it was more intimate, more real. The darkness was something that flowed through you, blotted into your skin, ran in your veins. In the depths of the Tetragode Kettle could feel the Noi-Guin’s web of shadow-links all around her, alarms pulsing from one to the other. And something more, something dark and awful, like a spider lurking in the midst of that web, some many-legged monstrosity ready to scurry out to devour any foreign body trapped in its strands. Something singular. In charge.

Kettle continued to go deeper, taking care to leave as few traces of her passing as possible, choosing the narrow paths over the broad, winding her way down among the roots of the mountains. She wrapped herself in the clarity trance, filling every detail with meaning. Twice she found traps. The first barbed and rusty blades anchored beneath the soft mud covering an area of tunnel floor, the second a fall of rocks, ready to drop at the tug of a thin, black chain that crossed the stony ground. They marked the limits of the Noi-Guin territory, designed to thwart infiltration via any of the unknown ways snaking beneath the Grampains.

There are times to attack fast and relentlessly, allowing your foe no moment to regroup, but that is a tactic best suited to a place you know well or have studied in diagrams to the point at which you could navigate it blind. Having rung the Tetragode’s doorbell, the best policy, the one Sister Apple would suggest from her study of the grey tomes, was to lie low, let the defenders expose and exhaust themselves, and then to learn what needed to be learned before striking and striking hard.

* * *

• • •

THE WAITING GAME is a difficult one, especially when a friend is in danger. The Noi-Guin would not know that Nona was the target of the intrusion—they had many enemies after all—but she would be high on the list of reasons for the attack. Probably they would move Nona, maybe even kill her and be done with it. Kettle didn’t think so, though. If they thought Nona the target then Nona was also the bait. The Noi-Guin were vengeful. And even if they were not vengeful an attack on the Tetragode was an attack on their reputation and could not be allowed to go unpunished. If Nona were killed then perhaps the attackers would melt away, uncaught, and that could not be permitted.

Kettle thought that the most probable course of action for the Noi-Guin, if they believed Nona to be the likely target, would be to torture her in the hope of drawing the attackers out. They would consider the possibility that she was thread-bound to at least one of her would-be saviours. The only other alternative would be to accept that the Noi-Guin who had brought her in had allowed herself to be tracked to the Tetragode by more conventional means, and that was unthinkable.

Kettle settled herself deep at the end of a chain of choices committed to memory and waited. She crouched in the chill, utter darkness of a passage where perhaps no person had ever been before in all the long millennia since the stream that carved it had found a different course. She wrapped herself in clarity, ears open to the smallest suggestion of sound, her mind touching the darkness, sensitive to any vibration that a shadow-worker’s power might cause. She ate, chewing slowly on the trail-biscuit from her pack, letting the moments slide by and accumulate into hours. And Nona, summoned along the thread-bond by the terror that Kettle had experienced approaching the Tetragode, albeit suppressed and channelled into more useful forms by her training, now found her grip on the nun’s perception slipping. As fear mellowed into calm, and boredom became the most immediate threat, Nona’s place in the back of Kettle’s mind became smaller and smaller. At the last she began to feel the cold of her cell and the shivering of her own flesh, which unlike Kettle’s was wrapped in nothing but the torn remnants of a smock.

* * *

• • •

NONA’S EYES SNAPPED open. “Damn.”

What? Where were you? Keot burned across her throat, just below the collar.