The apu joined her. He was chewing some kind of processed green leaf; he offered her some, but, moving subtly away from him, she declined. He said, ‘Quite a sight if you’re not used to it. And even if you are, it astounds you sometimes.’

‘It doesn’t look like the other side of a cylinder. It’s like another world suspended over this one.’

The ColU murmured in her ear, ‘That’s natural. The human eye was evolved for spying threats and opportunities in the horizontal plain, and so vertical perceptions are distorted—’

‘Hush,’ she murmured.

Ruminavi looked at her quizzically.

She said, ‘I can see we’ll be coming down from the puna soon.’

‘Yes. Which is why they put this chuclla here. The last stop before the descent. A place to acclimatise to the thinner air, if you’re coming the other way.’

‘And the land below …’

‘It’s a kind of coastal strip. The rivers pour down off the puna and spread out, and you have sprawling valleys, immense deltas. Very fertile country, nothing but farmers and fishers. They grow peppers, maize. Should take us half the time we travelled already to cross.’

‘Five more hours? And then what? You said a coastal strip. The coast of what?’

‘Why, of the ocean. Goes all the way around the waist of the world.’ He pointed to the sky, in the direction they’d been travelling, the direction he and his soldiers called east. ‘You can see it at night sometimes. Spectacular by day, of course. We’ll be crossing by the time the sun comes up.’

‘Crossing it?’

‘It’s spanned by bridges, for the railway, other traffic. We’ll go rattling across it without even slowing down.’

‘How long to cross the ocean?’

‘Oh, it’ll be getting dark again by the time we reach the eastern shore.’

The times, the distances, were crushing her imagination. Fifteen, twenty hours more, and she would still be travelling within the belly of the artefact. ‘And beyond the ocean?’

‘Ah, then we come to the antisuyu. The eastern country, all of this side of the ocean being the western, the cuntisuyu. And if you went on all the way to the eastern hub it would be another fifteen hours.’

‘But we won’t be going that far.’

‘Oh, no. Only five, six hours to home. My home and yours.’

‘Which is? What’s it like?’

‘Jungle. Hacha hacha. You’ll see.’ He grinned, his teeth white in the pale light. He held out his leaves again. ‘You sure you won’t have some of this coca? Makes life a lot easier to bear …’

She shook her head, and once more backed away from him. He followed, ineffectual, evidently drawn to her but, thankfully, lacking the courage or guile to do anything about it.

CHAPTER 43

On Per Ardua, that first ‘night’ after Beth and Earthshine came through the Hatch, it rained for twelve hours solid.

The sound of the rain on the tough fabric of her shelter was almost reassuring for Beth. Almost like a memory of her own childhood, when, as her family had tracked the migration of the builders and their mobile lake her mother had called the jilla, they had stayed in structures that were seldom much more permanent than this.

But no matter how familiar this environment felt to her, Beth was painfully aware that she was alone here, save for an artificial being that seemed to be becoming increasingly remote – even if he was, in some sense, her grandfather. ‘And that’s even before he drives off over the horizon,’ she muttered.

‘I’m sorry?’ Earthshine sat on an inflated mattress beside her, with a convincing-looking representation of a silver survival blanket over his shoulders.

Over a small fire – the first she’d built here since she’d left for Mercury, all those years ago – she was making soup, of stock she’d brought with her in her pack, and local potatoes briskly peeled and diced and added for bulk. Plus she had boiled a pot of Roman tea. She had flashlights and a storm lantern, but in the unending daylight of Per Ardua enough light leaked through the half-open door flap of the tent for her to see to work.

‘Nothing,’ she said. ‘Just rambling. I keep thinking I haven’t slept yet, not since the Hatch.’

‘But it’s only been a few hours,’ Earthshine said gently. ‘We’ve seen a lot, learned a lot. It just seems longer.’

‘Maybe. Only half a day, but you’re already planning to light out of here, aren’t you?’

He shrugged, and sipped a virtual bowl of tea. ‘I see no reason to hang around here any longer than it takes the support unit to make itself ready to travel.’

‘Where?’

‘The only logical destination on a planet like this.’

‘The antistellar?’

‘Of course.’

‘Which means a trek across the dark side,’ she said.

‘You are free to come with me,’ he said evenly. ‘There is no rush; we can make preparations. You could even ride on the support unit if you wish. We could rig up some kind of seat.’

‘Thanks.’

‘Alternatively, you are free to stay here, or go where you wish. I will donate some components from the support unit, if you choose that course. A kit: basic environment sensors, food analysers, a medical package to supplement the first aid available from your suit.’ He passed his fingers through the fabric of her sleeve, wincing as he did so. ‘Remember, I won’t need it.’

‘I lived off the land here once, with my family, and I can do it again.’ She did a double take. ‘Our family.’

He didn’t respond to that.

‘Why are you going to the antistellar?’

‘In search of answers.’

‘Answers to what? What’s wrong with being right here?’

He clenched a fist. ‘This is all wrong. It wasn’t supposed to be this way. I smashed Mars to make them listen to me – to us, to humanity.’

‘You mean the deep bugs in the rocks.’

‘The Dreamers, yes. As I call them. Our puppet masters, or so I’m coming to believe. They have been disturbing our worlds, trashing our histories, wrecking our painstakingly assembled civilisations with impunity. Well, no more! I made them listen. I made them respond.’

‘Their answer was the Hatch on Mars.’

‘Yes. A Hatch which brought us here. But this isn’t good enough. Not a good enough answer.’

‘I don’t understand—’

‘This is Proxima! Oh, I can’t deny it, Beth, it must be, a Proxima somehow old and withered, but … Proxima, the nearest star. But I wanted to be taken to Ultima, the furthest star of all our legends – or the equivalent for the Dreamers. The place where the answers are – the place where I’ll learn at last why it is they do what they do. And,’ he said darkly, ‘maybe I will stop them. Maybe I can still be Heimdall to their subterranean Loki … Yes, I forced an answer out of them. A response, at least. But it’s not enough. So I will put them to the question again.’

‘How?’

‘I don’t know yet. When I get to the antistellar I’ll figure it out.’

She thought that over. ‘Somehow I feel you’re wrong. I don’t know how or why … They brought you here. Maybe the answer you seek is right here, and you just aren’t seeing it.’

‘That’s possible. But even if so it can’t do any harm to go and search some more, can it?’

‘A lot of people thought you should be stopped from pursuing your ambitions. That was always true, all the way back to your early days on Earth, wasn’t it? Even before you became—’

‘What I am now? When I was merely Robert Braemann, bona fide human being, and busy breaking the law to save the world? Or at least that’s the “I”, of the nine of me, who interests you. And then I became Earthshine, a Core AI, one of three rogue minds, once again breaking humanity’s laws to save it. And again they never forgave us. Now here I am alone, trying to save—’

‘The world? Which world?’

‘All the worlds, maybe. I don’t know.’ He was silent a while; the rain continued to hiss on broad Arduan leaves. ‘Do you think you will come with me? I ask for purely practical reasons. The timescale, the preparations—’