And already city lights burned on the night side.

A Mars with thick air and cities and brimming canals! A nineteenth-century fantasy back where Penny had come from, made reality here. Maybe, she wondered sometimes, her commanders had been too cautious in their use of the great, unexpected benison of the kernels. So much more could have been done with that magical torrent of energy – as long as you didn’t care about the consequences for what you were reshaping.

‘I know what you’re thinking,’ Ari said.

‘Do you?’

‘That this is not the Mars you left behind in that other history of yours. Well, it’s true. But soon it will not be the Mars that was here when you arrived.’

‘It will be Earthshine’s Mars.’

‘Yes. That god you brought into our reality is remaking a world. Höd – Ceres – is on its way, spiralling closer with every revolution around the sun. Just now it is …’ He thought about it, glanced at Mars for orientation, and pointed to his right. ‘That way. An object visible to the naked eye, from the Martian ground.’

‘Why are you here, Ari? What do you want of me?’

‘You’re going to speak to Earthshine.’

‘That’s obvious. He summoned me. Although I don’t know what he wants of me.’

‘I knew you would not listen to me, if I had approached you on Terra, or during the flight. It is only now as we prepare to descend that I feel able to speak to you – to make you listen – only now that I can impress on you the urgency of what I ask.’

Penny glanced at Kerys; the trierarchus, tethered to a support bar by one hand, looked on impassively. ‘Kerys, do you know what this is all about?’

‘Leave me out of it. I do know Ari went to the top – to Dumnona itself, the headquarters of the Navy – he pulled a lot of strings to be allowed a berth on this mission.’

‘And all for this one moment, Penny Kalinski,’ Ari said.

‘For what? What do you want, druidh?’

‘It’s simple enough. You will talk to Earthshine. Listen to what he says. Repeat it to me when you return – or if not to me, to the trierarchus, to Dumnona, anybody. Find out what he truly intends, and tell us.’

‘You know what he intends. To terraform Mars, to make Mars live.’

‘That’s what he tells us. I’m convinced there’s something else. Something hidden. We will be landing you there,’ and he pointed to the Hellas basin. ‘We call this Hel. Earthshine has established some kind of habitat here, at the deepest point of the deepest basin on Mars. That is where his personal processing-support unit is now situated. Why there? We don’t know. And he has an establishment a few hundred miles to the north.’

In what Penny’s culture had known as Syrtis Major. ‘Yes?’

‘From the way you have described your own career, I would think you would be familiar with such a place. Penny Kalinski, as far as we can tell from the radiations being released, that is a laboratory where kernels themselves are being studied. Your speciality. Now, why would Earthshine need to delve into the physics of the kernels, if as he claims his priority is the vivifying of Mars?’ He smiled coldly. ‘Perhaps he will ask you to work there alongside him. Perhaps you will write more “papers” for the “journals” read by the learned people of your world—’

Penny snapped back, ‘Oh, give it a rest, you manipulative bore. How’s your wife, Ari?’

‘I have no wife,’ he said neutrally.

‘Fine. Then how’s your daughter?’

‘Mardina’s ten years old now, and she despises me. I see her once a year, and that’s by a court order I had to have drawn up.’

‘So she should despise you. What do you want from her, or her mother? Forgiveness?’

‘I’d settle for understanding. I meant everything for the best, for everybody. Yes, including Mardina!’ Suddenly he looked lost, vulnerable. ‘Couldn’t you tell her that for me?’

But now the trierarchus drifted between Penny and the druidh, and led him away. And a few minutes later a junior crew member found Penny and told her she needed to prepare for a landing, on Mars.

CHAPTER 20

As seen from the crude rover that bounced Penny over the surface from the landed Ukelwydd, Earthshine’s base on Mars was an array of glass boxes with their faces tipped towards the sun, low and pale in the northern sky of Hellas – ‘Hel’. For Penny, the base was a nagging reminder of something she’d seen before.

The rover docked neatly with a port, and she made her way through an airlock with the assistance of a couple of young women in the rough uniforms of the Brikanti Navy. Then she was led through offices filled with pallid Martian light. In the gentle one-third gravity she was able to walk with no more support than a stick.

They arrived in a wide, airy room, and Penny paused to inspect it, leaning on her stick. At its centre was a single desk, behind which sat a man in some kind of business suit, indistinct in Penny’s rheumy vision despite the relatively bright light. The desk overlooked a pond, a smooth surface crossed by languid low-gravity waves, and reflecting the faun sky. Again memory nagged.

She was allowed to walk forward alone, her footsteps silent on a thick swathe of carpet, a subdued brown to match the Martian colour suite. To get to the desk she had to hobble around that central pond, which was glassed over and filled only with a kind of purplish scum, she saw; there were no plants, no fish.

As she neared the desk, the man stood gracefully. Tall, dressed in a sober business suit and collarless shirt, he might have been fifty. On his lapel he wore a brooch, a stone disc carved with concentric grooves. He was Earthshine, of course.

‘Please,’ he said in his cultured British accent. ‘Sit down. Would you like a drink? Coffee, water – you always liked soda, as I recall.’

‘When I was eleven years old, maybe. I’ll take a water, thank you.’ She lowered herself stiffly into a chair before the desk.

Earthshine tapped the desk surface, which opened to allow a small shelf to rise up bearing a bottle of water, a glass. ‘I’m afraid you’ll have to pour it yourself.’

‘I know.’

He sat, fingers steepled, regarding her. ‘Thank you for coming.’

‘Did I have a choice?’

‘Not given the logic of our past relationship, and the nature of your own personality. Clearly you are as curious as ever. But I would not have compelled you to come. Could not have.’

‘I’m starting to remember all this. Well, mostly. That carpet should be – blue?’

‘That would hardly fit with the Martian background.’

‘And with a huge Universal Engineering Inc. logo. And Sir Michael King sitting behind that desk, not you.’

‘It is to be hoped Sir Michael survived the war, in his bunker under Paris.’

‘It seems unlikely. Even if that version of Paris actually exists any more.’

‘Quite so. I have tried to recreate the conditions as you remember them from your first visit to the UEI corporate headquarters—’

‘Solstice, Canada. Many years ago. The first time we met. I was summoned there with my sister.’

‘Although,’ Earthshine said carefully, ‘since that event came before the great sundering of your own personal history, she would say she went there alone.’

‘And the pond,’ she said, looking over her shoulder. ‘Weren’t there some kind of stunt gen-enged carp in there? Whereas now there is just scum.’

‘Actually the probe contains something much more exotic than an engineered fish or two. Martians,’ he said sepulchrally. ‘Real-life indigenous Martians, extracted from mine shafts and other workings.’

That took her by surprise. ‘Really? Bugs from the deep rock?’

‘That’s the idea. In fact, in our reality the Chinese discovered them, in the process of excavating water as part of their own terraforming efforts. The specimens I have inspected appear the same as the Chinese discoveries – the pivoting of history made no difference to them. The samples in the pond are real, by the way, though much of the rest of this environment—’