“I thought the Ictha would be good at swearing, what with all those long nights to practice!” Quina went to the doorway. “I’ll teach you some better ones later.”

Maya’s struggling head emerged wide-eyed from the top of her parka. “You’re going to rescue your brother?”

“Yes.” Yaz frowned. The Ictha would call it throwing good spears after bad. The Ictha couldn’t afford grand gestures. Weakness had to be abandoned on the ice. Grow too old, get sick, become injured, become a burden and the harsh equations of wind and cold dictated that you be left. No one would come after her. She had committed the crime of weakness and the Pit of the Missing was her sentence, though somehow the regulator had commuted it. She set her jaw, defiantly. This was a new world. New rules applied. “Yes, I am. And soon. Coming with me?”

Maya paled at that and edged toward Thurin, waiting in the doorway. Thurin shot Yaz another glance, this one unreadable. Quina had already left the hut.

“Come on!” Thurin waved to go, even though Kao was still struggling to get his other overboot on and lace it.

“I feel better like this.” Yaz stamped her boots, the rock no longer grating against the soles of her feet. Back in the clothes she’d been wearing when she dropped, Yaz felt like an Ictha again. She looked like one too. The mix and colour of her skins declared it. She wondered how long it would take for her differences to fade into the patched oneness of the Broken. She wondered if the guilt would ever fade. If she would ever lose the feeling that it had been her fault that dragged her here. Her failure that deprived the Ictha of a pair of able hands and took her parents’ first and last child from their tent.

The others started up the path at a half run, laughing as Kao bellowed curses after them. Yaz followed, deep in her thoughts, Kao labouring behind her, still snatching at his boot. He began to catch them up in the second great chamber, puffing and blowing.

“Call that running? Arka told us to hurry!” Quina sped off, showing a remarkable turn of speed. “Come on!”

Thurin made to chase after her but paused when he saw that Yaz had come to a halt. “The Ictha girl needs to rest?”

“No . . .” Yaz wasn’t sure what it was but it was . . . something. The river that runs through all things remained hidden from her, she had used its power on the previous day to match the endurance of her tribe and it would be some time yet before she could find it again. But even when the river lay beyond her reach there were echoes of it everywhere, lines, infinitely many and infinitely fine, running from and to every part of every thing. She only had to defocus her vision to see those threads, and sometimes, like now, they encroached without her asking. They had pulsed in the air around Regulator Kazik while he inspected her at the mouth of the pit and they vibrated now, throughout the cavern, as if they were a net across which something heavy were advancing. “Over there.” She pointed without seeing.

“No . . .” Thurin spoke the word in disbelief.

“What is it?” Maya moved to stand behind Kao as he joined them, puffing, and with angry words waiting only on the breath with which to express them.

Yaz could now see two points of light in the direction she’d aimed her finger. Far across the dark cavern. Hard white light of a kind she had never seen. Not the soft red of sunlight or the warm orange of flame.

“With me!” Thurin shouted. “Run!”

Yaz took off after Thurin, the others following, all but Quina, who had gone off ahead and become lost from sight in the gloom. “What is it?”

Thurin saved his breath for running. Yaz pounded after him, praying no unseen fold of the rock would trip her, and from behind came a growing clatter of hard feet hitting stone, a clattering and a clashing and a thrashing. Whatever the thing was it was gaining on them at a frightening rate. In seconds it would be on them, and with the cavern wall looming ahead they had nowhere to run in any case.

“In! Crawl!” Thurin reached the cavern wall at a point where the base failed to quite meet the floor, leaving a narrow gap between ice and rock. Yaz threw herself after him, cutting her hands on the grit to save tearing the knees from her leggings. Skin grows back, hides don’t, was an old Ictha saying.

“Deeper!” Ahead of her Thurin was on his chest, scraping further in.

Kao and Maya launched themselves after Yaz and a heartbeat later their pursuer hit the wall with a thump that shivered through the ice. A shower of pulverised fragments fell in a white veil across the entrance to the gap.

“Quick! Get in deeper!” Thurin sounded desperate.

“I can’t!” Kao’s thick body jammed two yards short of Yaz’s position.

“Grab hold!” Yaz had already half turned to wedge herself deeper and now turned further to reach back for Kao’s outstretched hand. Behind the boy she could see what seemed a forest of black legs through the clearing debris.

“Pull!” Kao screamed.

Yaz hauled, trying to anchor herself, but Kao proved more tightly held and instead they only succeeded in dragging her forward a few inches.

Behind Kao’s scrabbling feet something large and black clanged against the rock and a blinding white eye filled the crevice with light.

“Try again!” Thurin shouted and above Kao a layer of ice several inches thick shattered and fell away as Thurin exercised his power.

Yaz hauled and Kao lurched forward.

Through slitted eyes Yaz could see a variety of limbs invading the gap, some sinuous like black metal tentacles, others rigid and articulated, iron arms with too many elbows and skinning knives for claws.

Kao jerked his foot back as one of the clawed arms reached for it.

Thurin shouted behind them. “Back further! It opens up!”

In a nightmare of squeezing and pushing, Yaz and Kao burrowed deeper until at last, as Thurin said, the ice roof lifted slowly, then swiftly, and they found themselves in a bubble the size of an Ictha tent, the almost-dark broken by the faintest glow from the walls.

“What in the long night is that thing?” Yaz almost had to shout to hear herself above the grinding and fracturing noises coming from the cavern wall though it was now separated from them by ten yards of ice.

“A hunter from the city,” Thurin said. “It shouldn’t be here. They hardly ever leave the ruins.”

“But what is it?” Yaz demanded.

Thurin only shook his head. Behind him the glare from the hunter’s eyes was a diffuse white glow reaching through the yards of ice.

Yaz crouched down to peer back the way they’d come. The hunter had lifted its head to get in close and was reaching for them blind. The longest of its arms raked the rock two yards shy of their chamber but could reach no further. The only light now was a deep red one, so deep it was almost black at times, radiating out from between the plates of armour covering the creature’s body. Yaz couldn’t make sense of the thing, it looked like a random collection of pieces, segmented together. “How long will it stay?”