Indeed, as she walked, she saw no sign of the kind of ‘animal’ life that had once been common here – not that the distinction between animals and plant life here had been quite the same as on Earth – no kites, no builders, no fish-analogues in the rivers. Nothing but plants and stromatolites and simpler organisms like lichen, competing for the light. The silence of the world was profound, broken only by the wind, the occasional hiss of rain, and their own voices.

And yet they saw more traces of humanity, or at least of the world humans came from. More splashes of the brilliant green of Earth’s version of photosynthesis, standing out against the darker hues of Arduan life. These were mostly what looked like much-evolved versions of food plants, potatoes, yams, beets, soya beans, even peas and grape vines, and what looked like laver, a descendant of a genetically engineered seaweed, choking water courses. Earthshine speculated that, untended, these survivors had reverted to something like their original wild forms – the tubers of the potatoes, for instance, were much reduced from the bloated varieties favoured by humans. Beth carefully selected samples to enhance her stores.

Survivors: that was what they were, terrestrial stock clinging on amid the native life of this world. And yet Beth thought she saw a kind of silent cooperation going on here. In the flood plain of one river, terrestrial potatoes covered ground that looked too damp for most Arduan life, but Arduan stems sprouted in ground consolidated by the potatoes’ roots. In an isolated forest copse she found terrestrial vines growing up the trunk-stems of Arduan trees. And so on. Even if there had been animals, the herbivores from each domain of life couldn’t have digested samples from the other; the biochemistry, coming from a common stock, was similar but not identical. But perhaps, she thought, the dissimilar forms of life were evolving deeper ways to cooperate. Just as she and her virtual grandfather were two more dissimilar life forms finding ways to get along.

That came to an end a couple of weeks into the walk, with two hundred kilometres covered. It was when she saw her own shadow starting to stretch before her on the ground, meaning that Proxima was no longer overhead but was beginning to set, that she realised she’d come far enough.

The parting, once she’d separated out her gear, was awkward. Almost jokey.

‘At least you’ll know where to find me,’ said Earthshine.

‘And you me.’ She forced a smile. ‘Even if we couldn’t be further apart on this planet. Literally.’

‘That’s true,’ he said gravely. ‘Especially taking into account the tidal bulges. When I get the chance I intend to establish some kind of communication system. Small satellites perhaps. You have comms gear—’

‘In the pack you’ve given me, the slates. I know.’

They stood in stiff silence.

‘Goodbye, then,’ Earthshine said.

‘Goodbye.’

He made a show of climbing aboard his carriage, his support unit on its recently fabricated wheels, and off he went, at last accelerating up to the speeds he’d wanted to make in the first place. It somehow comforted her to know that he was continuing to support his human virtual form.

Then she turned away, and began the long walk back, alone.

CHAPTER 49

AD 2234; AUC 2987; AY 796

Eight months after the Romans had arrived at Yupanquisuyu, Inguill came to their ayllu. She was accompanied by officials, and a healthy squad of troops. She arrived in a cart drawn by two muscular-looking alpacas, causing a stir in the village. Such animals, it seemed, were rare and reserved for the elite.

Such a personage as the quipucamayoc, record keeper of the empire, did not travel lightly, it seemed, and not without heavy protection. Mardina was learning that the antisuyu was thought of as bandit country, from which the Sapa Inca and his family and court were protected by layers of security: the rainforest, and then an ocean, and then the open stretches of the altiplano, and then a climb of hundreds of miles through vacuum before you came upon the fortifications of Hanan Cuzco itself … And yet here Inguill was, in the mouth of the jaguar.

The visit was a big event for the ayllu. Although Inguill and her followers had arrived entirely unannounced, the ayllu was expected to feed and house them. Tents and lean-tos were hurriedly erected – even the curaca, Pascac, the local leader, had to give up his house. Meanwhile the fastest young runners and yanakuna slaves were sent dashing to nearby communities to call in favours, and they returned with food, stashes of coca and other potions, blankets and bedding and other luxuries.

Inguill, however, seemed interested in none of this. She set up a kind of court in Pascac’s house, and spent one night resting to recover from her journey, and consulting with Ruminavi the tocrico apu among other advisers. Then, through Pascac, she peremptorily summoned the senior Romans: Quintus Fabius as the obvious leader, and whoever he chose to bring with him – but, she specified, that had to include Chu Yuen the slave boy, with his mysterious pack.

Before the meeting Quintus Fabius gathered his people outside Pascac’s house. Mardina noticed that while Quintus and his soldiers had become accustomed to wearing the readily available ayllu garb, today he and Titus Valerius had defiantly changed back into the remains of their military costume, though of course without weapons, armour or legion insignia. Mardina supposed this was some statement of cultural defiance. Mardina herself was happy to stay in the local clothes, including her round felt hat, which she’d decided was quite fetching.

Quintus spoke quietly, in rough camp Latin. ‘Do not translate, please, Collius. Let us not be overheard for once.’ He gestured at the group. ‘So here we are. I suspect most of you would prefer not to be brought before this rather sinister woman.’

‘Sinister and with power over us all,’ grumbled Titus Valerius.

‘Yes, Titus. But we are an anomaly here in Yupanquisuyu – an anomaly in this version of history …’

‘True,’ murmured the ColU from the usual pack mounted on a nervous-looking Chu Yuen’s back. ‘And from the very beginning it has been this woman Inguill, of all the Inca locals, who has seemed to have perceived that most clearly.’

‘Well, she is the empire’s chief record keeper,’ said Michael the medicus. ‘If anybody knows the history, it’s going to be her.’

‘Correct,’ Quintus said. ‘And since, as far as I know—’ and as he said this he glared at Titus ‘—none of us have misbehaved terribly – none of us have done anything to bring ourselves to the undue attention of the authorities here, as far as I know …’

‘You can rest assured about that, sir,’ Titus rumbled.

‘Presumably Inguill has come here to address loftier questions. Well, I suppose I was going to have to face this at some point, but at least I don’t have to be alone. So I am bringing you into the arena with me, my friends. You, Titus, the heart of the century – and its belly. You, Michael, as the nearest to a philosopher we have. You, of course, Collius, as she has requested Chu Yuen—’

The ColU said, ‘Even if she doesn’t know of my existence, yet, or my true nature.’

‘And me?’ Mardina asked, baffled. ‘Why am I here?’

Quintus smiled at her, reassuring. ‘You are here because you represent our past, Mardina. Half your blood, after all, comes from beyond two jonbar hinges. And with your youth you also represent our future – and whatever future we have depends, at least for now, on the goodwill of the Sapa Inca. I want you at my side so that Inguill sees that.’ Then he surprised Mardina by clasping Chu Yuen on the shoulder. ‘And you, Xin. When I assigned you as the bearer of Collius it was a random choice – I was barely aware of your existence, I did not know your name, or care. Yet you have come through so much with us, and you have borne yourself and your strange burden well. I am glad you are with us today.’