There was no one to ask. The old master controller-maker, Crafter Barkus, had died last year. What notes he’d made on a lifetime’s work were almost unintelligible, and the rest of his knowledge had died with him. Tiaan had learned everything he’d cared to teach her, and had made small but useful improvements to controllers, some of which had been adopted at other manufactories. However, at twenty she was too young to rise from artisan to crafter. The manufactory was sorely in need of someone with greater experience.

Through the door her fellow workers were talking among themselves, no doubt about her. Tiaan felt oppressed by their knowing looks, their unsubtle judgments and pointed jokes about not having done her duty. A twenty-year-old who had never been with a man – there had to be something wrong with her. It was not said meanly, more in puzzlement, but it hurt just the same.

There’s nothing wrong with me! she thought angrily. I just haven’t met the right one. And not likely to, among the misfits and halfwits here.

Two of the prentices sniggered, looked up at her cubicle then guiltily bent over their grinding wheels. Flushing, Tiaan hurried out of the workshop. She wove her way through the warren of clerks’ benches, past the clusters of tiny offices, the library and the washing troughs, then between infirmary and refectory and out through the wall into the main part of the manufactory.

Out here the racket of metal being worked was deafening and everything stank of smoke and tar. She turned left toward the front gate, crossing a bleak yard paved in dolomite in which a warren of buildings had been thrown up as the need required. There were drifts of ash and dust everywhere; the sweepers could not keep up with it. Every surface was covered in a film of oily soot.

‘I’m going down to the mine,’ she said to Nod, gate attendant for the past thirty years.

The old fellow had a white beard so long that he could tuck the end into his belt, but not a hair on his head. He raised the iron grille. One tall gate stood open. Nod held out his hand. No one was supposed to go out without a chit from their foreman.

‘Sorry, Nod,’ she said. ‘I forgot again.’ Gryste always made a fuss so she was reluctant to ask, even though going to the mine was part of her job.

Nod looked over his shoulder then waved her on. ‘I didn’t see you. Good luck, Tee!’ He patted her on the shoulder.

Tiaan found that rather ominous. He’d not wished her luck before. Shrugging on her overcoat, she went out into the wind. The path down to the mine was slushy, the snow on either side brown with soot from furnaces that burned night and day. At the first bend, just before the forest, she looked back.

The clanker manufactory carved an ugly scar across the hillside. From here it comprised a grimy series of scalloped walls ten spans tall, with slits high up and battlements above them. Guard towers hung over the corners, though they were seldom manned, the manufactory being hundreds of leagues from the enemy lines. From the rear a cluster of chimneys belched smoke of various hues – white, orange and greasy black.

Tiaan did not think of the place as ugly. It was just home, and work, the two concepts like joined twins. It had been home since her mother, the pre-eminent breeder in the breeding factory at Tiksi, had sold Tiaan’s indenture to the manufactory at the age of six. She had been here ever since. She occasionally went to Tiksi, three or four hours’ walk down a steep and stony path, but the rest of the world might not have existed.

There was no time for it. Life was regimented for war and everyone had their place in it. The work was tedious, the hours long, but crime was unheard of. No one was afraid to walk the streets at night.

To her left, another path tracked the snow under the aqueduct, then across the gash of the faultline before winding up the mountain to the tar mine. On rare hot days up there, tar oozed out of the shattered rocks and could be scraped into buckets. Mostly, though, the miners hacked solid tar from the drives or followed erratic seams of brittle pitch though the mountain. It was the worst job in the world, and few survived to old age, but someone had to do it. The furnaces of the manufactory must be fed. Its clankers were vital to the war. And the war was being lost.

Controllers were just as critical. Tiaan could imagine how the soldiers must have felt, attacked by ravening lyrinx and realising they had no protection because their clankers had stalled. She could not bear to think that it might have been her fault.

She hurried along the path to the lower mine, where the hedron crystals were found. It was twenty minutes’ walk down a steep decline and Tiaan had plenty of time to fret, though she was no closer to a solution when she reached the main adit.

‘Mornin’, Tiaan!’ Lex, the day guard, nodded at her from his cavern like a statue in a temple. His ill-fitting false teeth sat on the counter, as usual. Sometimes the miners hid them, sparking a frantic search and emotional outbursts.

‘Morning, Lex. Where’s Joe today, do you know?’

‘Down on fif’ level,’ Lex mumbled. Without his teeth it was hard to make out what he was saying. ‘Take six’ tunnel on right an’ follow to end.’

‘Thanks!’ Selecting a lantern from the shelf, she lit it at Lex’s illegal blaze, a brazier full of fuming pitch shards, and set off. The sides of the tunnel were strewn with broken wheels off ore carts, cracked lifting buckets, tattered strands of rope and all the other equipment that accumulated in a mine as old as this one.

When Tiaan reached the lifting wheel she found it unattended. She rang the bell but it was not answered so she got into a basket, eased off the brake and wound herself down. Level one, level two, level three. The shafts ran deep and dark and old here. It had been a mine for hundreds of years before the value of the crystals was recognised. As she passed the fourth level a blast of air set the basket rocking, almost blowing out her lantern. At least the ventilation system was working. There had been bad air down here the last time she’d come. One of the miners had nearly died.

Cranking herself down to the fifth level, Tiaan stepped into the tunnel and made sure the brake was off, otherwise no one could use the lift and the attendant would have to come down on a rope to free it.

It was pleasantly warm on this level, a nice contrast to outside and to the manufactory itself. It was always cold there unless you worked near the furnaces, and then it was unpleasantly hot. However, the artisans’ workshop was right up the other end of the manufactory, on the frigid south side. Tiaan had been cold for most of her life.

She trudged on. Every chunk of waste rock had to be carried up and out, so the tunnels were no bigger than necessary to gain access to the ore and the veins of crystal. Often she had to go on hands and knees, or slip through a gap sideways with the uneven edges scraping her ribs. The rock here was pink granite, impregnated with veins that writhed like blood vessels in a drunkard’s eyeball. The miners came for gold, platinum, copper, tin and silver, though her old friend Joeyn delved for something much more precious – the crystals from which the magical hedrons were made. Some were as big as her fist, and it was these Joeyn especially sought. Only certain crystals could be used for making hedrons. Few other miners could tell which ones to take and which, apparently identical, to leave behind.

Wriggling around a knob of layered granite glinting with mica, Tiaan saw a light ahead. An old man sat in an egg-shaped space, his lantern, pick and hammer beside him.

‘Joe!’ she yelled. ‘I’ve found you at last.’

‘Didn’t know I was lost,’ grinned the miner, climbing to his feet with many a groan and a clicking of aged joints. Joeyn was a small, wizened, skinny man, at least seventy, with a long sharp face and skin impregnated with mine dust. He was Tiaan’s only true friend. He gave her a hug that made her ribs creak.