‘But – further out where the vapours froze, the primordial vapour clouds collapsed on a large scale, trapping rock fragments, metals – notably iron … The products were giant planets – a core the size of an Earth, under oceans of liquid, and towering layers of air above that—’

  Pulet nodded. ‘Neptunes – presumably named for some other lost prototype. Jupiters. So there were Neptunes in the sky where I was born and was raised. In the Neptune belt. Also Jupiters, even more massive, a giant of gases. Whereas you—’

  Mott said, ‘We call our home worlds, this region, the Inner Worlds. And yours—’

  ‘The Outer Worlds, I suppose.’ Pulet laughed. ‘How unimaginative. The Inner Worlds. I imagine that most of your neighbours would say the same. And this place is … cosy. Comfortable. Easily habitable.’

  ‘So why have you come here, Protector? What do you want?’

  But Pulet stood his ground, spoke calmly. ‘We come here out of necessity, frankly. Our technology has adapted to the circumstances our ancestors found themselves in. We are short of metals, Commodore.

  ‘In the broadest sense. Short of accessible metal, at least. I admit that. Oh, we can even mine rocky moons, but the great lodes of metals are trapped in the hearts of our giant planets, beneath crushing atmospheres thousands of kilometres deep – that is out of our reach. That has limited us, our expansion. And without metals—’

  ‘Ah. With limited access to metals, you are limited in terms of heavy engineering. And smart technology. Computing. Control systems—’

  And Ulla saw it. ‘That’s why you have come here. And that’s why you use slaves. Or one reason. Because you haven’t the computing technology to run your machines, to keep your civilisation running—’ She was growing angry. ‘Your machines are dumb. At least compared to our equivalents. I’ve seen that joke of a life-support system in the slave hold. Your civilisation is dumb. Dumb, as well as cruel, wasteful – coarse. You must use human beings as we use machine components. And that’s why you’ve come here. You want the resources of our worlds … And you want us, as slaves, to dig them out for you—’

  The commodore rested her hand on Ulla’s arm. ‘Easy,’ she murmured. ‘Stay calm. You are perceptive, quick-thinking, bold – outspoken. And this protector likes you. I need you at my side through this, Commander Breen. But – don’t push it. You’re too useful to get yourself thrown out the airlock.’

  Ulla forced herself to calm down, even to smile.

  The protector seemed amused by this exchange, as if by precocious children.

  Mott turned to the protector. ‘Very well. So your long-term ambition is evidently to steal our resources, our metals – and, surely, to enslave the peoples of the Earth belt in the process. Preferentially the young and fit, I imagine—for the iron-core mines?’

  Pulet waved his hand. ‘Such emotive language. Enslave. This is a matter of economics, Commodore Mott. And surely there have been precedents in your own history—’

  ‘Not in our civilisation. Not as far back as we have records, all the way back to First Landing so far as we know—’

  ‘Ah.’

  That phrase had caught Pulet’s scholarly attention, Ulla saw, knowing him well enough to understand his distraction.

  ‘First Landing. Is that what you call it? We say, the Arrival … We both have, evidently, fragmentary folk memories of the same event, the founding of a strand of mankind in this place, this Hearthspace … We should share what we know. No matter, no matter, not for now. Focus, Ciren! As my teachers always would say when I daydreamed of other times, other places …’

  Mott glared at him. ‘Enough with your bragging, enough of your people’s ugly, barren history … Why are you here now? What is it specifically that you want from us now, Protector? From me?’

  ‘Simply put, I want to negotiate directly with your government. Yet I know nothing of your government, its structure, its capabilities – its needs and desires. Through you, I hope to establish a bridge for negotiation. For I would far rather negotiate with you, with it, than—’

  ‘Than what? Negotiate about what? Slave-raiding? More acts of aggression? Which is all you have brought us so far.’

  He shrugged. ‘Slavery is a mere economic transaction, like any other – a trade in people rather than goods. I can see that this is not palatable to you. But it need not be difficult. It is simply economics.’

  Mott said, ‘So, again, what is it you want of us here and now? Before you talk us all to death.’

  Ulla saw the scholar’s own officers grin at that.

  ‘Harsh words. Simply this: tell me how your government works. Where is it?’

  Mott sighed. ‘Very well. A reasonable demand. After all, you’ll need to know how to find it when you negotiate … the surrender of our worlds to you, so you can construct a regime of eternal slavery?’

  He smiled. ‘I knew you would understand. Now, your worlds?’

  ‘You understand we are a society spread around the Hearth, at this radius. Where the Hearthlight is evidently strong enough to sustain human life – Earthlike worlds. These are the Inner Worlds. Rich, living, close-by worlds.’

  ‘Just as, at my home radius, we live off the ice giants and their moons—’

  ‘The core of our culture consists of six of these many worlds, six of a respectable size – all capable of sustaining life – and spread roughly equally around a suitable orbit. The Six Earths, we call them – and we number them. Warm enough for life, not so cold for ice to form. Our governance is spread out over these worlds. But there are several other colonised worlds. We are a sprawling community – maybe not so diffuse as in your own cold ranges – but still our government sprawls, by design. For the purpose of resilience in case of disaster, and to avoid concentration of power.’

  Pulet smiled. ‘Good. That appeals to the orderly side of my intellect. Six worlds, equally spaced. And if the orbital distances of the six from the Hearth at the centre are the same, then for orbital stability their spacing must be the same, roughly, as the shared orbital radius itself—’

  ‘Correct. Thirty thousand AU. Roughly.’

  ‘Roughly.’

  ‘These six worlds were numbered in order of discovery, not orbital order. chosen for the neatness of the spacing at this epoch – some day they will drift apart – and to enable an equal reach in terms of governance distance. Earths One to Six.

  ‘We also inhabit worlds of other types – Mars types, we call them, some like smaller, cooler Earths. Many surprisingly rich in water, which can be mined easily given the low gravity. And there is a class called the Venus type, where we have learned to farm the clouds …’ She eyed Pulet. ‘One detail may interest you, if you are the scholar you claim to be. Some of these worlds host indigenous life. Or they did.’

  The protector’s eyebrows went up at that. ‘Interesting indeed. Similar to Earth life, like our own?’

  Mott shrugged. ‘I’m no expert. I do know it’s based on carbon-water chemistry like our own, similar molecular structures.’

  ‘Ah. Fascinating. Not identical? Perhaps these worlds have germinated their own biospheres – sharing the same carbon-water scaffolding with their own unique, differently evolved designs.’ He flexed his fingers. ‘And do these Mars worlds share the products of those biospheres? Can hardy organisms travel through the void, when worlds approach each other?’

  Mott shrugged. ‘I don’t know about that. I do know about Venus worlds. A third kind of Earth-sized planets, but with thick atmospheres, arid, baking hot surfaces.’

  Pulet grunted. ‘Useless then.’

  ‘Actually not,’ Mott said. ‘We found a way to use such worlds. The high clouds on such worlds, far above the hot landscapes, can be rich in water. And where there’s water, and plenty of light—’

  ‘Ah. Life can prevail. Perhaps not originate in such a place—’

  ‘Our ancestors created floating cities, broad, light-gathering cities like trays full of fertile soil, and began to raise crops. Crops from seeds brought to this place by the progenitor ship from Earth—’

  Pulet seemed rapt, his eyes alight.

  Ulla almost felt fond of him. This side of him, the curiosity, the sense of wonder.

  But now he asked a blunt question. ‘One more rocky-world type. We call it a Mercury. Like an Earth, but smaller, usually formed close-in to the Hearth, heavily pounded during its formation, any volatile water, gaseous atmosphere driven off by the heat, leaving little but a metallic core and a skim of a rocky crust. Do you have such worlds … ?’

  Mott seemed to hesitate before answering. ‘We do, yes. And I see the appeal for you. A lode of naked metal, waiting to be mined?’

  Now Pulet asked Mott, ‘And do you mine such worlds? Are your habitats, spacecraft manufactured there, bathed in the heat of the Hearth?’

  ‘We do—’

  ‘Ha!’ said Captain Erbas. ‘Take us there and you will have a glimpse of the truth of our society. The heart.’

  Pulet raised his eyebrows. ‘Surprisingly poetic, Captain. But with a grain of truth.’ He rubbed his hands. ‘Well. After all that I long to visit these worlds, blue Earths, red Mars clones, farms in the sky …

  ‘Ah. But diplomacy must come first.’

  Mott’s grin was cynical, Ulla thought. ‘And by diplomacy you mean war.’

  ‘Oh, it need not come to that—’

  ‘You’ve already made first contact, with the 45. You overwhelmed us, enslaved the crew – the surviving crew – you introduced yourselves by making war—’

  ‘Well, then, we must try to make a better impression when we meet your government. You said the governance is spread across six Earths. And which is the nearest from our present location?’

  Mott glanced at Ulla, nodded.

  Ulla, a bridge officer, knew that much. ‘Earth 4, as it happens. About a thousand astronomical units from our present position.’

  Captain Erbas grinned. ‘A stroll, Protector. I assume you’ll wish to get there as soon as possible?’

  ‘Excite me! What does “as soon as possible” mean for this fine craft?’

  ‘Depends how much sail we put on, sir. At one gravity’s acceleration we can be there in ninety days.’

  ‘Impressive,’ Pulet said. ‘Gives the natives that much less time to, umm, prepare for our arrival. Can you do any better?’

  The captain’s grin widened. ‘I can give you two gravities and knock off seven days.’

  Ulla leaned forward. ‘Oh, you can’t do that. The people in the slave pit – two gravities for so long – we aren’t acclimatised for that – we don’t have the equipment—’

  Captain Erbas grabbed her shoulder, pushed her back, hard, into her couch, hard enough for her to have troubling breathing.

  And Mott leaned over, muttered, ‘Don’t fight it. You’ll only give them an excuse to get rid of you – and I imagine there’s plenty on the crew who find your relative freedom irritating … All for your big mouth. You push your luck, child. You can’t fight this one. As for the thrust regime, we’ll find a way to prepare the crew. Training routines. Medical stuff, a buddy system … We’ll find a way.’

  Erbas let her go, and she lay still, struggling to breathe.

  Two gravities, all the way to Earth 4. Two gravities, for eighty days.

  There are children down there.

  Mott seemed to perceive her fretting.

  ‘We’ll find a way,’ Mott said, over and over. ‘We’ll find a way. You’ll see, Ulla. You’ll see.’

  She fell into oblivion.

  9

  Over the following days, Ulla and Lieutenant Nusma tried to work out a regime for the slaves, and indeed most of the crew, that would enable them better to survive the hardship. Two gravities.

  So a regular furlough was announced. For six hours per day, the drive was to be shut down altogether – the miraculous fabric of the huge sails turning itself transparent, so that the light of the dazzling pinpoint of the Hearth shone through it, unimpeded.

  That added to the target journey time, but Ulla was able to persuade Pulet that, overall, the time saved by a scramble of repairs and reinforcing of the structure would pay dividends – as well as relieving the pressure on the human crew.

  And in those intervals, Nusma and Ulla rushed around the slave deck, trying to get to every accident victim, 45 crew or slave alike.

  In the process, Ulla got to know more of the slave deck herself. Its strange landmarks, the hovels with their roofs open for inspection from the balcony above, the larger hovel with the sinister name of ‘brothel’ … A more meagre shack called the ‘hospital’, which she thought of as a glimmer of hope, or charity, even in the dark of this place, maintained solely by the slaves, sustained by trash, filthy blankets, dirty bottles with dirtier water, even some scraps of medication, bandages, scavenged from earlier medical interventions.

  In one corner, Ulla always noticed, beneath a stretch of the cylindrical wall, there was a pool of murky water, ankle-deep, presumably an artefact of damaged floor panels.

  A puddle in a spacecraft.

  The people were mostly lounging, apathetic, a few pursuing some task or other.

  And, with a guard always at her side, she finally inspected for herself the enigmatic mass of machinery that Ashe had long ago identified as the hub of the ship’s main life-support system.

  What Ulla saw, as she had seen from above, was a mess of grimy machinery, with access hatches through which children – mostly – would climb.

  Ashe, accompanying her, said, ‘I’ve been able to dig into the detail of this, the engineering, a little more. It really is a closed-loop system, run in the end on the energy of Hearthlight …’

  A resource loop comprising nothing but human beings, algae, Hearthlight, and some reasonably smart gadgets.

  Ashe told Ulla that every human being needed around four kilograms of stuff, every day, including food, oxygen, water. They got energy to move around from ‘burning’ the food in oxygen, and they produced waste in the form of breathed-out carbon dioxide, water sweated or pissed out, and waste solids. Shit, mostly.

  ‘But the clever part is what happens then,’ Ashe said. ‘Inside this clumsy gadget. Assuming they use the same basic technology we have—’

  ‘Maybe inherited from whoever came here first, to the Hearth?’

  ‘Or they may have rediscovered it for themselves. As we did, I was told.

  ‘Look. A human being consumes food, air, energy. In this system all their waste products are then processed, and broken back down again for reuse. It’s all done with algae, with the power of the Hearthlight, by photosynthesis.

  ‘You need a “mechanical supercritical water oxidiser”. Running on Hearthlight, or some other power source, such as nuclear – the oxidiser processes human waste, and feeds back water, oxygen, nitrogen, salts and other materials. Stuff that is used to feed algae farms. The algae, growing, emit oxygen. And then humans breathe some of the oxygen and eat the algae in the form of processed food …

  ‘Essentially you have a closed-loop ecosystem, a cycling of materials, involving just algae and human beings, with some technological help. Run on Hearthlight, or maybe the ship’s atomics. All this is ancient, robust technology, and evidently is effective, even efficient, and enables spectacular pan-Hearthspace voyages on epic scales.’

  ‘But—’

  ‘But,’ Ashe said, ‘nothing is perfect. You have to move stuff around in there. You have to fix stuff. You get blockages, components break down …

  ‘I think it’s fair to say that the main purpose of the slaves on board this ship, during flight anyhow, is to buffer the life-support cycles. They, their piss and shit and breath, make up over half the biomass aboard, probably. And fixing it day to day all boils down to forcing enslaved children to crawl around through hatches and ducts, beneath the floor of the slave pen, through ordure and waste and stink and green smears you can never wash off your hands …’

  ‘Every day.’

  ‘Every day,’ Ashe said. ‘And, probably, if everything broke down, I’ve heard hints that there are emergency protocols.’ He leaned closer, whispered. ‘Where the slaves are consumed directly.’

  ‘You mean—’

  He nodded gravely. ‘It wouldn’t last for ever, but maybe long enough to get to some safe harbour. To get the crew there, I mean.’

  As he spoke, all this slotted into place. Odd scenes Ulla had witnessed, hints from careless talk of the crew, the black humour of the guards …

  ‘And that is why we have to fight the Hierarchy,’ said Ulla. ‘ For our children.’

  And Ashe said, in a kind of quiet growl, ‘For our children. Never this.’

  Despite how much she had usefully seen about the true workings of the ship during this voyage, she felt a huge relief – as did all concerned, Ulla thought – when at last Earth 4 loomed out of the dark. The twenty-day voyage wound to a close, the great sail was folded down, the two-gravity thrust was at last reduced to a mere one-sixth. The feeble gravity of a satellite, a moon of the original Earth – so the scuttlebutt went.

  And in the final approach, as a rare concession to morale, Pulet and Captain Erbas invited Ulla, Mott, Nusma and others to Pulet’s observation lounge to view the approaching planet.

  Ulla herself, despite her dismay, disgust, and a selfish fear evoked by the slave-ship she had found herself trapped in, could not help but be entranced by this vision of a world that looked like a jewel, hanging in the sky.

  An Earth made into a toy.

  Nusma seemed genuinely interested. ‘Is this the Earth you came from?’