‘Wow,’ Penny said drily. ‘If only they could talk, the bar tales they could tell.’

‘In fact, that’s why I’m here, Penny. They may indeed have stories to tell. Let me show you. Step back now.’

She moved a few paces away from the pond. Earthshine clapped his hands.

And the office space, the desk, the carpet – even the pond, even the sky of Mars – faded from view. Walls and a ceiling congealed around Penny, and she found herself suddenly enclosed in a kind of elevator car, with a display on the wall of descending lights.

‘Going down,’ Earthshine said smoothly.

‘I can’t feel the motion.’

‘I’d need to tap into your deeper brain functions to simulate that. I figured that you’d rather pass.’

‘You figured right …’

After only a few minutes the doors slid back.

Earthshine led her out into a kind of cave, maybe a hundred metres across, the rock walls roughly shaped, the light coming from fluorescents attached to the walls. It looked like a classic Brikanti project to Penny, the heavy engineering made possible by kernel energies, if you were unscrupulous enough to use them on a planet. But there were also storage boxes here, white but scuffed, and stamped with ISF logos and tracking markers. One complex cylinder she remembered as the storage unit that had housed Earthshine’s consciousness aboard the Tatania.

And she saw scientific instruments set out on the floor, and standing on tripods by the walls. All these were connected by a mesh of cables over which she and Earthshine stepped now, gingerly, a network that terminated in contacts with the walls, plugs and sockets and deeply embedded probes.

‘How deep are we?’

‘Kilometres down. Obviously the facility requires some physical manpower down here – the Brikanti have no robots, after all – but the workers can survive only hour-long shifts. It’s not just the heat and the airlessness, it’s the sheer claustrophobia.’

‘This is ISF gear,’ she said accusingly. ‘The science stuff. You cannibalised Tatania for all this.’

‘Well, why not? The remnant hulk was only scrap to the Brikanti, of no value to them.’

‘Maybe. But it wasn’t yours to exploit either. And that pillar – you are in there, aren’t you? The processor and memory units that support you. Now here it is, kilometres deep. You built yourself another bunker. Just like the one you had on Earth.’

He smiled. ‘Well, wouldn’t you, if you were me?’

‘And you’ve come down here to commune with a bunch of Martian microbes.’

‘You can mock if you like. But that is essentially correct. Penny, on Earth even solitary microbes show complex behaviour. They can respond to gravity, heat, light, the chemical signals that betray sources of food or the threat of toxins. They have selves, in a sense. They can communicate with each other, Penny, interact, through chemical exchanges, even through gene swaps. And through that communication they form communities. Like biofilms, or stromatolites: coalitions of many species, in shelters that control humidity, temperature, sunlight, and provide food storage, defence – even a kind of “farming” of plants and lichen. Did you know there are certain slime-mould bacteria that hunt in packs, like wolves?

‘And, working together on a larger scale, they can achieve monumental things. On Earth it was the microbes, the planet’s first inhabitants, that put oxygen in the air, and loaded the soil with minerals and nutrients – they created the foundation on which complex life forms like ourselves could be constructed.’

‘OK. And on Mars—’

‘On Mars, because the surface conditions were so hostile, the microbes have had nothing else to do but grow their own communities, ever deeper and wider, ever more complex. Penny, I am detecting collective entities down here, all embedded in the rock, spanning kilometres at least. For all I know such communities might span the whole planet; Mars is small and static enough for that to be possible.

‘They swap information using strings of DNA, or their version of it, and tangled-up proteins. Every so often phages – targeted viruses – will pass through these communities in waves, taking out diseased or malfunctioning members, or injecting fresh DNA, in a kind of global upgrade – an evolution through learning and cooperation rather than through competition. It’s almost like watching my own information stores synchronise … We, my brothers and I, were aware of such entities on Earth.’

‘You were?’

‘We, after all, were also minds vast and distributed, buried deep in the terrestrial rocks. But the thinkers are stronger here, more clearly defined, on a world without the gaudy clutter of surface life. There is a profound unity here, with a complex distributed structure that would take decades to map, or more.

‘But these entities do more than just survive. More than just repair and upgrade. The density of the information flow, as best I’ve been able to measure it, is far too high for that. They are conscious, Penny. Vast diffuse entities locked in the rock – and yet aware of the wider universe, surely, as light and radiation sears the planet’s surface, as the geology shifts and heaves. Everything is very slow – the energy density is so sparse you’d need a collector the size of your classroom to gather the power to light up a bulb. The dreaming communities can only be aware of the slowest events, the grandest. But they have plenty of time down here. Plenty of time to dream.’

‘Communities of microbes, then, dreaming in the rock.’

‘That’s it. That’s my vision. A twentieth-century thinker called Teilhard de Chardin spoke of the noosphere, from a Greek root for “mind”. Earth was wrapped in a biosphere, a life sphere. And within that was a sphere of mind – which de Chardin conceived of as human civilisation, of course. Here I have found a noostratum, Penny. A geological layer of consciousness, of dreamers, deep in the rock of Mars, between the heat below and the lethal cold above. And perhaps there is a similar stratum on every rocky, life-bearing world – Earth, a world like Per Ardua.’

‘OK. And you came here purposefully, didn’t you? You came to Hellas, the lowest point on Mars, and you started drilling. You came in search of these deep bugs—’

‘I suspected some kind of structure was there, yes.’

‘But why?’ She tried to think it through. ‘And what has this got to do with your wider concerns? I remember you on the Tatania, as we fled the war. How could I forget? In those awful moments when the wash of light from the destruction overtook us. I remember your anger. “They have unleashed the wolf of war,” you said. And by “they”, you meant—’

‘The Hatch builders.’

‘I thought, in those moments, your purpose seemed clear enough. You were going to hunt them down, if you could. Take revenge. What have these deep bugs got to do with it?’

‘I’ll show you.’ He clapped his hands.

CHAPTER 21

Abruptly the walls of rock dissolved, the litter of science and engineering gear vanishing. Suddenly they were out on the surface of Mars, standing on rust-red soil under a night sky, the only light coming from the last vestige of a sunset reflected from streaky clouds to the west, and a single visible star – a dazzling lantern, a planet, maybe Jupiter – no, she realised, it must be Ceres, Höd, a thousand-kilometre-wide ball of ice and rock on its way to an ultimate destination in Martian orbit …

She was in the open, there was no dome over her, no glass-walled corporate building around her. The transition was sudden. Penny stumbled, and felt her throat close up. After a career in the ISF she was an experienced enough astronaut to feel a plunge of panic to be stranded on the surface of a hostile world without life support.

‘But none of this is real,’ she forced herself to say, and she heard her own voice in her ears. ‘Of course not. Because if Mars ever got the chance to kill me it would do so in less than a heartbeat.’