‘I’m sorry people got hurt,’ Caleb said, meeting the older man’s gaze. ‘But that was always a risk. You must have known that.’

  ‘Yeah, I knew,’ Stone nodded. ‘And if everything else had gone well I think I could have accepted that. But it didn’t.’

  He sighed, pulling up a chair and reversing it. He sat, one arm folded over the backrest, the other absently massaging his right knee.

  ‘You know how melerithyst is formed?’ he asked.

  Caleb didn’t answer. It didn’t seem that sort of question.

  ‘The mineral has a crust,’ Stone continued. ‘Like the shell of a sumpkroc egg, except even thicker. The outside is inert and worthless, but if the deposit is large enough and the shell gets thick enough then you sometimes get a little pearl in the centre, like a gemstone. Still worthless, mind, unless you put just the right amount of charge through it. Then the stone sparkles. I suppose it’s pretty enough if you like that sort of thing. The rich people uphive will pay a lot for a really pure gem. I gather they make it into jewellery or something.’

  He shrugged at this, as if the rationale behind such behaviour was quite beyond him.

  ‘You can’t make a living out of it, chiselling through a boulder to extract one shiny bauble. But you stumble across a big seam… Suddenly that’s real money, providing you can get to it. Extracting the stuff is delicate work, of course. Once that shell is broken a tiny contaminant can ruin everything inside.’

  ‘The landslide…’ Caleb whispered, a horrible sinking feeling drawing over him.

  ‘Indeed,’ the older man nodded. ‘All the melerithyst. All that money. Gone. Buried in the dust. We’ve already started excavating, hoping some of it is salvageable. We might get lucky.’

  He did not sound hopeful, and suddenly looked a lot smaller.

  ‘We didn’t cause the landslide.’

  ‘Oh?’ Stone frowned. ‘Those weren’t your grenades going off?’

  ‘Yeah,’ Caleb conceded. ‘But it was only partially our fault. It was mainly the Ambot.’

  ‘Ambot?’

  ‘Yeah, they’re like a–’

  ‘I am of Orlock, the House of Iron,’ Stone replied icily. ‘I know what an Ambot is.’

  ‘Right, well the miners must have been using it to excavate the ore – that’s how they finished so fast. When we–’

  ‘Where is it?’

  ‘What?’

  ‘The Ambot. Where is it?’

  ‘Buried?’ Caleb suggested. ‘Maybe it dug its way clear and wandered off. I don’t know.’

  ‘Well, once it digs its way back we can renegotiate the situation. Until then I decide what we do with you.’

  He regarded them in turn, his fingers drumming on the backrest.

  ‘I’m sure we can be of better use outside this cell,’ Caleb began. ‘I’d be happy to–’

  ‘No,’ Stone said, shaking his head. ‘You won’t be happy. Not once you see what your job is going to be. You ever worked on a clearance crew before?’

  ‘I haven’t had the pleasure.’

  ‘Then you are about to receive an education.’ The older man rose from his seat. He winced slightly as he straightened his knee, and Caleb heard the distinct whine of servos. He unhooked a weighty set of keys from his belt, unbolting the door. The cell bars ground open, protesting as they scraped across the rock floor. Their captor entered the cell, his footsteps still echoing with the uneven gait. He approached Caleb, looking him over one final time. Then he unlocked the manacles. They fell to the ground with a satisfyingly loud clang. Caleb rubbed his wrists; it did little to ease the discomfort of where the metal had dug into his flesh, but there was such a thing as protocol.

  He turned to Iktomi, expectant. She remained cross-legged on the floor. Their captor made no move to release her.

  ‘Aren’t you going to free us both?’ Caleb asked.

  ‘You’re not free,’ the older man replied. ‘You’re just going to work. I’d keep you cuffed if I thought you were an actual threat.’

  ‘I don’t want any trouble.’

  ‘See, there I actually believe you,’ Stone said. ‘You were meek as anything when we carted you away, despite having blood and brains splashed across your face. Shame the same could not be said for your friend.’ He glared at Iktomi and tapped his swollen eye.

  ‘You put your hands on me,’ she muttered, refusing to meet his gaze.

  ‘I was trying to pull you out. As was the man whose arm you broke.’

  ‘Your skull hurt my hand,’ she said, holding up her bandaged finger. ‘Call it even?’

  Stone cursed and turned away, seizing Caleb by the arm.

  ‘Can I just have a moment?’ he pleaded. ‘Just… to say goodbye.’

  Stone rolled his eyes, but released his grip. ‘You have a minute. And keep it clean.’

  Caleb nodded in thanks, squatting down beside Iktomi, clumsily trying to take hold of her hands despite the manacles. ‘My love,’ he said, staring longingly into her rather baffled eyes. ‘I swear we will be together again.’

  She blinked, confusion morphing into something akin to panic. He leant closer, pressing her to him in an awkward embrace, his mouth resting against her ear.

  ‘Can you escape?’ he whispered.

  ‘The cuffs?’ she asked. ‘Maybe. I could pick the lock if I had a pin or small piece of bone.’

  ‘Stone swept this place clean,’ Caleb said. ‘Well, maybe it would be safer to stay here for now. If things get really dire I’ll signal you.’

  ‘How?’

  ‘You’ll know it when you see it.’

  ‘So, you don’t know, then?’

  ‘Not as such.’

  ‘Enough,’ Stone said, seizing Caleb’s shoulder. ‘You have a debt. It’s time to repay it.’

  Stone marched him through Hope’s End, one arm hooked behind his back. There would have been little point struggling; the older man’s grip was like steel. Literally. His right hand was entirely mechanical, the bionic limb strong enough to shatter bone.

  For the most part, the people of Hope’s End seemed to ignore Caleb, and he did his best to keep his head down and his eyes low. But he caught the occasional exchange of words, and from the corner of his eye he could see small groups gathering, merging like tributaries as they followed the two-man procession. Without Iktomi to watch his back he felt vulnerable. Perhaps Stone read something in his expression. The older man slowed a fraction, his grip easing.

  ‘Just keep your head down.’

  ‘That’s what I’m doing. But I still get this sense people are eyeing my neck a little too closely.’

  ‘Maybe,’ Stone said. ‘But they won’t cross their overseer.’

  ‘And when your back is turned?’

  ‘It will be different once you get to the mine. And once the main shaft and the compound are clear I’d prefer it if you both disappeared back uphive. That is, providing your woman can refrain from injuring any more of my people.’

  ‘You are very lucky she didn’t hear you call her that,’ Caleb murmured as they drew towards the workshops. A line of minecarts were propped on their sides, secured by industrial clamps, while the workers buffed the magnetic runners clean. As Caleb approached, they turned as one, a dozen pairs of eyes staring balefully at him.

  ‘I’m dead, aren’t I?’ Caleb whispered, speaking mainly to himself. But Stone heard him.

  ‘No,’ the older man replied. ‘The mine has a code.’

  ‘My gang before my House, my House before all others?’

  The older man smiled. ‘Not that code. At least, not all of us. No, there is just an understanding that once you climb that mineshaft there is no room for rivalries and grudges. It doesn’t matter if you stole my wife or wronged my family. If two people get into an altercation up there, they can end up not only killing each other but also everyone else.’

  ‘I’d find that more reassuring if– sorry, did you say “up” there?’

  ‘Yes.’

  ‘I thought mines traditionally went down?’

  ‘If only we could. You dig a few feet through the ash and rubble and the bedrock is as tough as ceramite. We can barely scratch it, let alone mine it.’

  ‘Then where does the mineshaft go?’

  Stone nodded to the inverted mountains. Caleb’s eyes widened.

  ‘You go up those things?’

  ‘They are all we have left. We took all the easy deposits centuries ago.’

  ‘You know there’s a lake above us?’

  ‘Sinkhole? Yeah, we know.’ Stone chuckled. ‘How do you think we ended up with such unique scenery? Those stalactites, we call them the King’s Tears. That’s where the sump found weak points between the domes. It burned a path through, the rock running like wax, dripping through till it reaches the bedrock below.’

  ‘So, just to be clear, the upside-down mountains are actually funnels of acid-fused rock?’

  ‘That’s what formed them. They’re clear now. Mostly.’

  ‘So you aren’t worried about maybe poking a hole into the lake?’

  ‘We get leaks all the time. The rock melts and eventually seals the breach.’

  ‘That doesn’t sound so bad.’

  ‘At least, that’s what we think happens. Usually there aren’t enough survivors to be sure.’

  ‘I see,’ Caleb said. ‘Well, if I do get caught in an acid shower I’ll do my best to try to make some notes.’

  Stone smiled with genuine humour. ‘No need to panic just yet. You’re in the clearance crew, not deep excavation. I doubt you’ll be digging high enough to be at risk.’

  ‘I feel like you’re enjoying this more than you should.’

  ‘I enjoy no part of this,’ Stone replied as they drew to a stop beside the workshop. ‘I didn’t enjoy your little speech. I didn’t enjoy watching you raising my people’s hopes only to dash them. I didn’t enjoy watching those young men die when it all blew up in your face. I didn’t even enjoy watching you come to terms with how badly you messed this up.’

  ‘I really did want to help,’ Caleb sighed.

  ‘I believe you,’ Stone murmured. ‘But I also think you were more interested in playing the hero than actually being one. Do you feel like a hero?’

  Caleb didn’t answer. Stone presented him to the mine workers.

  ‘One more for your crew,’ he said, addressing the foreman. He was of average height and similar girth, clad in the same combination of leather and denim as the rest of the crew. Goggles adorned his head and a respirator hung around his throat. His hair was either greying or powdered by ash; it was hard to tell.

  Caleb smiled, even though he’d long since lost confidence in the expression. The foreman looked him up and down.

  ‘Fancy threads,’ the foreman said, rubbing Caleb’s torn and stained shirt between his fingers.

  ‘Thanks. They certainly were.’

  ‘I’m guessing from how you dress that you don’t have much experience mining?’

  ‘I’m used to crawling through narrow spaces. But besides that, no.’

  ‘Well, we can change that,’ the foreman said, grinning. ‘Providing you survive.’

  6

  Stone was true to his word, at least in the beginning. Caleb had been relegated to clearance crew, shoving ash into the minecarts as they endeavoured to clear the compound. He kept hoping to stumble across the Ambot, so that its presence might corroborate at least part of his story. When he finally heard the clank of his shovel striking metal he was ecstatic, until further investigation revealed that it was the body of one of the gangers. There was a las-burn on his thigh, and Caleb realised it was the man he’d shot. Perhaps if he’d been uninjured he’d have had a chance to escape; it was impossible to know for sure. The body was dragged away and loaded into the cart along with the rest of the curiosities extracted from the dust.

  When the settlers uncovered the toppled minecarts everything changed, the mine clearing as workers surged towards the discovery, discarding shovels as they dropped to their hands and knees, brushing the ash with their fingers. The first bag of melerithyst was split, its contents little more than a brown mulch, but they continued digging as the foreman caught hold of Caleb.

  ‘I need to pull some more people down here. You’re needed upstairs,’ he said, jabbing his thumb towards the main shaft, where the cage awaited.

  Two prospectors flanked the entrance, each protected by a thick leather apron. They wore goggles, their mouths covered by ancient respirators. Both nodded as he approached, gesturing wordlessly to a backpack that was about half his height. As he heaved it into place part of him wondered if this was just part of his punishment. It might explain why the rucksack seemed to be filled with rocks.

  The mine’s cage had been welded from old bulkheads, the gate a mesh of steel. There was room for perhaps half a dozen on the platform, but only the three of them ascended, the winch whirring as it raised them into the darkness.

  Caleb had lived most of his life in the cramped confines of the underhive. He was familiar with the warren of pipes and tunnels and knew how dangerous it could be, but it had still always felt somehow natural to him. The mine was different. He was an invader venturing into hostile grounds; every twist in the tunnels felt like an ambush waiting to happen. The tunnel walls had an unpleasant sheen, almost like rotten flesh, and the air still burned his throat in spite of his goggles and respirator. Even without the risk of bullet or blade, prolonged exposure to the fumes would no doubt prove fatal.

  The prospectors surged ahead, exchanging monosyllables as they examined the branches of the tunnel, marking off sections with incomprehensible symbols; perhaps warnings or directions. Caleb stumbled, struggling to drag his feet over the rough terrain. Ahead the tunnel branched in two, the left passageway clear, the right a mess of broken pipes. Caleb made for the clear path, but one of the prospectors’ hands snaked out, barring his way. The man reached into his pack, rummaging, withdrawing an extendable metal pole. It stretched out before him, tapping the walls and floor as he slowly moved along the passageway.

  A dozen tendrils suddenly surged from cracks in the tunnel, their bladed tips stabbing at the pole.

  Lashworms.

  The creatures’ bodies would be buried deep in the rock, safe from retaliation, while their bladed tails sought to tear a meal from anything that stumbled too close. The prospectors marked the tunnel entrance with a red cross, and the three of them picked an awkward path down the passage that ran parallel.

  Beyond lay a chamber of buckled iron – a fragment of the Ironcrown of old preserved in the rock. It was at least twenty feet high and wider still, a framework of warped iron bulkheads. But the metal was tarnished, tinged with a sickly green veneer, poisoned by the toxins in the air. The prospectors slowed, exchanging worried looks. They trod warily across the slanted floor, testing the corroded iron with needles of glimmering silver, wiping the metal on silken cloths and peering intently at the residue, as though discerning the future from Ironcrown’s entrails. They were meticulous, each taking two steps and repeating the process as they made their way through the chamber. They had almost reached the end when one of them shouted, thrusting his needle into the air.

  It was stained emerald green.

  More worryingly, steam was rising from the metal.

  The first prospector seized Caleb’s arm, dragging him from the chamber, the second hurrying beside him, swinging a brass handbell. As it rang others joined it, a procession of miners joining them from branching tunnels as they made for the cage. Only a handful could descend at a time and the rest waited in silence, their gaze intent on the shaft. Caleb glanced to the prospector waiting on his right. He still held the silver needle, though it was now bent, the tip dripping onto the rock.

  Outside, the light cycle had shifted to dusk, the dome lights dimmed and tinted a warmer shade. The minecarts were now partially excavated, though most of the melerithyst ore had spoiled and was now brown mush. Still, a few stones had survived – gems of pink flecked with gold. They had been painstakingly preserved in transparent membranes. It was all that remained of the priceless mineral. He was glad they had left it out to see. It was gratifying to fully quantify the extent of his failure.

  The prospectors and foreman were deep in conversation, no doubt debating how to secure the mine. He took the opportunity to slip away, drifting silently along the compound wall, now halved in height thanks to the mine’s overspill. They would no doubt be after him as soon as they realised he had gone, but he wanted just a moment of quiet, away from the noise and the stink of sweat. The air was clogged with dust but still tasted so very sweet, freed from the acid taint that permeated the rock. He had never been so happy to see the dome lights flickering above like stars.

  Movement.

  He jumped, pressing himself against the compound wall. There had been a shadow. It only lasted a heartbeat, but it looked as though something had shifted on the wall above him.

  He peered through the amber haze. Nothing.

  Perhaps it was another malfunction – one of the dome lights failing. Still, he no longer felt the need for solitude. He turned, intent on returning to the settlers, when he felt something land almost silently behind him, and the hairs on his neck rose. He spun around just in time for a fist to slam into his face.

  It wasn’t the hardest punch he’d ever received, but it was perfectly placed; the cartilage in his nose cracked, tears flooding his eyes. Two more stinging jabs followed in rapid succession, snapping his head back. He could barely see or make out the silhouette rushing towards him. For one instant he thought one of the settlers was seeking payback, but the punches were too crisp, closer to a cage fighter than an angry miner.

  Another blow caught his chin and he fell, fingers scrabbling in the dust, hurling a handful into his assailant’s face. He’d hoped to blind them, but a visor shielded their eyes. Still, it took a moment to clear it, time enough for him to regain his feet and aim a kick at their knee. His opponent’s leg buckled but they recovered quickly, lashing out again with a series of hooks. Caleb tried to cover his head as best he could, but more and more were landing. A right cross hammered into his ear, throwing him off balance. Desperate, he swung as hard as he could but hit only air, his opponent neatly bobbing out of reach before swooping in to deliver another flurry of blows.