Thurin furrowed his brow and reached out toward the ceiling. He gritted his teeth and drew his lips back in a mask of effort. The fall of stones thinned out with just a handful more hammering into the small mound that had already formed. He grunted and they stopped entirely. “Ouch.”

Pome’s call reached them across the rock. “Your ride is nearly here, Yaz. Come out. You’ve no choices left.”

The sound came of iron feet ringing on stone as the hunter advanced a few yards to underscore its master’s point.

Quell held his hand out. “We should go, Yaz.”

Yaz pulled back, her mind working furiously. There was a hard logic at work here. The same cold weighing of benefit and loss that surrounded the pit. She couldn’t find the words to argue with it but that didn’t stop her wanting to fight against it.

Far above them the cable and the lifting cage would be resting on the ice, waiting for the summoned coal-worm to arrive and follow the lead shaft, widening it sufficiently for the cage to follow down. The coal had fallen a great distance and the shaft behind it must be full of falling coal now backing up behind the blockage. The worm might even have started its work, pursuing its meal. But she hadn’t time to wait for the cage, and even if it was here now Pome wouldn’t allow the others to join her in it, or for them to take the food and the shelter they’d made. She hissed in frustration. They had come so close.

“Maybe this is the only way,” Erris said solemnly.

An idea hit Yaz, almost a physical blow. She rocked onto her heels. “Thurin! All that coal in the shaft . . . Could you make it burn? You once told me that you thought your flame-work was stronger than your ice-work.”

A rough laugh broke from him. “I have no idea! I know I can’t set things on fire. Once it was burning I might be able to do . . . something. I don’t know for sure—I’ve never properly used my flame-work. But we don’t have any fire and—”

Erris raised his hand between them and clicked his fingers. A small flame danced on the end of his thumb as if it were an oil lamp.

Thurin’s eyes widened in amazement. “How . . . ?”

Yaz waved the question away. “It doesn’t matter. Can you burn the coal?”

“What? No! It’s all the way up there and the flame . . . is . . . here . . .” Thurin seemed hypnotised by the flame. It started to flare, growing several feet tall in the instant before Erris shut it off. He looked surprised, alarmed even, and his thumb was left gently smoking.

Yaz remembered what Thurin had said about the need to use his ice-work at least every few days or the energies built inside him and burst out more strongly and with less control when he tried to use them. His flame-work had been building up for a lifetime. When he let the talent loose the results might be spectacular.

“Come with me!” She started running.

Yaz crossed the crater and scrambled out, breaking cover. She made for the coal pile that had fallen from the shaft over a hundred feet above her.

“Yaz of the Ictha!” Pome roared, spotting her at last.

Yaz ignored the shout. She splashed through the puddled meltwater and reached the coal. Behind her came Erris and Thurin but also Zeen and Quell.

“Can you burn that?” Yaz pointed at the pile. “And lift the fire up to the ceiling, then burn the coal in the shaft?”

“I have no idea!” Thurin stared up at the two small, icicle-hung holes in the ceiling far above, one blackened with coal dust. “And why would I want to?”

“It would bring the cage down fast,” Zeen said.

“There’s no telling what it would do,” Erris said. “There are too many unknown parameters.”

“One thing is pretty sure,” Quell said. “If it works then we’re all going to get wet.”

Behind them the hunter began to advance again, footsteps clanging on the rock. The gerants were coming too, making some kind of battle chant: “Hruh! Hruh! Hruh!” A deep, throbbing sound intended to terrify.

Erris clicked his fingers again to produce another flame and crouched to hold it to the nearest coal. “If you’re going to do this do it n—”

The coal seemed to suck the flame from Erris’s fingers, drawing it in as if it were a hole rather than just a black rock. For a moment Yaz thought the fire had disappeared but Thurin extended both hands, fingers splayed as though warming them at the sigil pot in the drying chamber.

In the next heartbeat the first coal turned orange, a fierce bright orange. The nearest coals were already a dull red where they touched it.

“Stand back.” Thurin’s voice shook, though Yaz couldn’t tell if it was with the effort of burning the piece of coal or with the effort of holding back.

She stepped away, glancing over her shoulder at the advancing line of Pome’s warriors. She was about to say “hurry” when a wall of heat pressed against her. As she stumbled and fell she became aware that the whole heap of coals had turned from black to a fierce orange-yellow and that the roaring in her ears came from the column of flame rising above the blaze.

Thurin stood silhouetted between Yaz and the burning coal, his arms raised as if conducting the inferno. The tongue of fire licked two dozen yards into the air but still couldn’t quite reach the star-speckled ice. Rather than growing, the blaze had begun to shrink already, its fuel expended in one extravagant gesture.

Yaz flung out her own hand from where she lay on the wet rock and the dozen fragments of her hunter’s star shot from her pocket, streaking into the column of fire.

What happened next occupied only a frozen fraction of a heartbeat, making no sense until her mind unfolded it in the next breath. A dark line passed over her head. An iron spear flung at Thurin’s back. The horror wouldn’t hit Yaz until after the spear had struck its mark. The force behind such a missile was enough to punch a hole through a man whatever bone or flesh might get in the way. Thurin’s first understanding would come after the crimson spear emerged from his ribs, flying away from him, leaving a trail of his own blood hanging momentarily in the air.

But somehow a figure managed to rise beneath the spear in the same instant it flew above them and to press upon it in such a way that it deflected upwards by just a few degrees. Zeen!

The skins over Thurin’s left shoulder danced as the spear sliced through them. The wind of the shaft’s passing fluttered the dark hair around his ear.

Yaz’s handful of stars rose in an accelerating spiral, travelling faster than she had ever made them fly before. She pictured the fire sigil in her mind and, as the stars broke from the top of the flames, the gyre they made carried the fire with them, a twisting vortex extending the tongue of flame to lick against the ceiling itself.

“Now!” she shouted.