“What kind of buildings must they have been to have had foundations like these?” Thurin asked. “I’ve seen it before and it still amazes me.”

“Foundations?” Yaz looked away from the stone “tooth” she had been examining.

“Your tents are held to the ice with pegs, so I’m told.” Thurin tilted his head.

“Yes, or the wind would take them.”

“Well.” He gestured around. “These are the city’s pegs. The Missing just drove them deeper than the Ictha do.”

Yaz opened her mouth but found no reply. Instead she gazed up at the distant ceiling, trying to imagine what the dwelling places of the Missing must have been like.

“What about the Missing themselves? Do we know how they looked?” Yaz had always been fascinated with the figures that some of the elders would carve from whalebone and whale teeth. In the darkness of the tent on the long night Mother Karrak could whittle away at a bone to reveal men and women inside, kettan figures, so detailed that come the dawn the Ictha would gather and laugh, recognising themselves and their family among those freed from the ivory. Perhaps the Missing had left a similar record. “Did they leave images?”

“Nothing.” Arka shook her head. “Nothing that lasted. But their lives were very different from ours. Eular thinks many of their possessions and their art may have been temporary and changeable, and their records locked away in ways we can’t understand. We do know though that they were of a similar size to us.”

“How?”

“Many of their chambers were of a size that would suit us. Their stairs also fit our stride.” Arka looked around. She had not stopped looking around since they had stepped out onto the flatter ground. “Stay vigilant. Allow a wonder to seduce your eye and a hunter may take that moment to pounce.” She waved them on, pointing out holes to hide in as they advanced.

Finally they reached the fractured edge of a large hole leading down into a darkness punctuated with individual points of starlight. A warm draft rose from the void, the first wind Yaz had felt on her face since her fall down the pit.

“The heat tells us that there are still many stars down in the city,” Arka said. “And the cavern tells us that our efforts have had minimal impact on that total.”

“How?” Quina scowled, clearly hating not to be able to work it out for herself.

“It isn’t dripping,” Arka said. “Only the east wall runs, where the advancing ice melts away at exactly the rate it advances. A stream carries the water off. The rest of the cavern is in equilibrium. The warmth just enough to sustain it.”

The rising air carried a stale smell along with muted undercurrents as alien as those of the forge huts. Yaz sniffed it with suspicion while trying to concentrate on what Arka was saying about minding their heads on the low ceilings.

“You wets are all terrible at climbing, and there’s really nowhere safe for you to practice, so this is it. Think about what you’re doing, where your hands are, where your feet are. This isn’t the ice.”

Arka carried on talking. Hulking beside Yaz, Kao muttered, “I should be on the ice. Not in a hole going into a deeper hole.”

Quina on his other side snapped back, “Seriously? How was any of this a surprise for you? Did you not notice that you were twice the size of your playmates? Your parents should have been preparing you for the gathering long before you came to the pit.”

“Perhaps his clan thought it a kindness not to tell him,” Yaz muttered. “Maybe all the adults knew and none of the children.” She had lived with the burden of the knowledge since her first gathering and it had soured the years left to her among her people. Ignorance might have been less cruel.

Arka took out an iron rod, longer than the one Pome had used to hold his star, and scooped a star from a small depression near the entrance. With its light to guide them she slipped easily down past the stone jaws and began to climb the slope of broken rock beneath.

Yaz let Kao go first. If he fell she wanted to be above him not below. Maya followed, nimble footed.

When it came to her turn to climb, Yaz found herself in immediate difficulty. She had lived her life on the level with nothing in her path but pressure ridges in the ice. The descents to the Hot Sea and the others that opened periodically when underwellings of warm water melted through the glacial sheet were treacherous things but the Ictha lowered themselves on hide ropes. Here she had no rope, only a complex, ever-changing surface to negotiate. By the time she reached flat ground again every limb trembled and sweat ran in trickles inside her furs.

“Gods in the Sea! I’m glad that’s over.” Yaz clambered down to join Thurin.

“Over?”

She saw that they were crowded on a ledge and that the steep slant of the tunnel continued, considerably closer to vertical than to horizontal. She peered over into the darkness. “How deep does it go?”

“Nobody knows. Scavengers say they’ve been as deep as the ice is tall, but I’m not sure how they could tell that.” Thurin offered a crooked smile. “It’s hard work. I’ve been down before and I’m glad of it, but I wouldn’t want to do it every day.”

The next stage of the climb brought them through narrow sections which Yaz found it impossible to believe a hunter could have fitted along. The rock seemed to press on her from all directions, constricting her chest even when not touching it. She felt the weight of all that silent stone, stretching above her for hundreds of yards.

“How could a hunter get out of here?” Quina asked the question for her.

“They can reshape and rebuild their bodies.” Arka squeezed between two great blocks of stone. “It takes them a long time. But they can do it. Which is one of the reasons we need to draw them away when they have someone cornered in a hole. Because given enough time they will reach you.” She vanished through and called from the other side. “Also some of the ways in and out are wider than this one. We’re using this one to avoid hunters.”

During the descent the character of the rock began to change, from some kind of natural fissure, broken open by the action of water and ice, to the strange stone of the long slope. They began to pass other openings, some square, some just new fractures and faults. Arka led them down into a ravine onto which rooms and chambers faced like open mouths, as if the bedrock had split wide and revealed them trapped in stone as bubbles are trapped in ice.

“Many of these chambers may have been where the Missing lived.” Arka lifted her star to reveal one as they descended past it. “Others were meeting places perhaps, or storage rooms, or housed markets or workers. We really don’t know. But what we are here for is metal, star-stones, and anything else that can be carried away. There is very little here that you can pick up that will not be of use to us.”