She took him to see Felka again, passing on the way through deserted nursery rooms, populated now only by bewildered mechanical animals. Felka was the only child left in the nursery.
Clavain had been deeply disturbed by Felka when he had seen her before, but not for any reason he could easily express. Something about the purposefulness of her actions, performed with ferocious concentration, as if the fate of creation hung on the outcome of her game. Felka and her surroundings had not changed at all since his previous visit. The room was still austere to the point of oppressiveness. Felka looked the same. In every respect it was as if only an instant had passed since their first meeting; as if the onset of war and the assaults against the nest - the battle in which this was only an interlude - were only figments from someone else’s troubling dream; nothing that need concern Felka in her devotion to the task at hand.
And the task awed Clavain.
Before, he had watched her make strange gestures in the empty air in front of her. Now the machines in his head revealed the purpose those gestures served. Around Felka - cordoning her like a barricade - was a ghostly representation of the Great Wall.
She was doing something to it.
It was not a scale representation, Clavain knew. The Wall looked much higher here in relation to its diameter. And the surface was not the nearly invisible membrane of the real thing, but something like etched glass. The etching was a filigree of lines and junctions, descending down to smaller and smaller scales in fractal steps until the blur of detail was too fine for his eyes to discriminate. It was shifting and altering colour, and Felka was responding to these alterations with what he now saw was frightening efficiency. It was as if the colour changes warned of some malignancy in part of the Wall, and by touching it - expressing some tactile code - Felka was able to restructure the etching to block and neutralise the malignancy before it spread.
‘I don’t understand,’ Clavain said. ‘I thought we destroyed the Wall, completely killed its systems.’
‘You only ever injured it,’ Galiana said, ‘stopped it from growing, and from managing its own repair processes correctly . . . but you never truly killed it.’
Sandra Voi had guessed, Clavain realised. She had wondered how the Wall had survived this long.
Galiana told him the rest: how they had managed to establish control pathways to the Wall from the nest, fifteen years earlier - optical cables sunk deep below the worm zone. ‘We stabilised the Wall’s degradation with software running on dumb machines,’ she said. ‘But when Felka was born we found that she managed the task just as efficiently as the computers; in some ways better than they ever did. In fact, she seemed to thrive on it. It was as if in the Wall she found . . .’ Galiana trailed off. ‘I was going to say a friend.’
‘Why don’t you?’
‘Because the Wall’s just a machine. If Felka recognised kinship with it . . . what would that make her?’
‘Someone lonely, that’s all.’ Clavain watched the girl’s motions. ‘She seems faster than before. Is that possible?’
‘I told you things had deteriorated. She’s having to work harder to hold the Wall together.’
‘Warren must have attacked it.’ Clavain said. ‘The possibility of knocking down the Wall always figured in our contingency plans for another war. I just never thought it would happen so soon.’ Then he looked at Felka. Maybe it was his imagination, but she seemed to be working even faster than when he had entered the room, not just since his last visit. ‘How long do you think she can keep it together?’
‘Not much longer,’ Galiana said. ‘As a matter of fact, I think she’s already failing.’
It was true. Now that he looked closely at the ghost Wall, he saw that the upper edge was not the mathematically smooth ring it should have been: there were scores of tiny ragged bites eating down from the top. Felka’s activities were increasingly directed to these opening cracks, instructing the crippled structure to divert energy and raw materials to these critical failure points. Clavain knew that the distant processes Felka directed were awesome. Within the Wall lay a lymphatic system whose peristaltic feed-pipes ranged in size from metres across to the submicroscopic, all flowing with myriad tiny repair machines. Felka chose where to send those machines, her hand gestures establishing pathways between damage points and the factories sunk into the Wall’s ramparts that made the required types of machine. For more than a decade, Galiana said, Felka had kept the Wall from crumbling - but for most of that time her adversaries had been only natural decay and accidental damage. It was a different game now that the Wall had been attacked again. It was not one she could ever win.
Felka’s movements became swifter, less fluid. Her face remained impassive, but in the quickening way that her eyes darted from point to point it was possible to read the first hints of panic. No surprise, either: the deepest cracks in the structure now reached a quarter of the way to the surface, and they were too wide to be repaired. The Wall was unzipping along those flaws. Cubic kilometres of atmosphere would be howling out through the openings. The loss of pressure would be immeasurably slow at first, for near the top the trapped cylinder of atmosphere was only fractionally thicker than the rest of the Martian atmosphere. But only at first . . .
‘We have to get deeper,’ Clavain said. ‘Once the Wall goes, we won’t have a chance in hell if we’re anywhere near the surface. It’ll be like the worst tornado in history.’
‘What will your brother do? Will he nuke us?’
‘No, I don’t think so. He’ll want to get hold of any technologies you’ve hidden away. He’ll wait until the dust storms have died down, then he’ll raid the nest with a hundred times as many troops as you’ve seen so far. You won’t be able to resist, Galiana. If you’re lucky you may just survive long enough to be taken prisoner.’
‘There won’t be any prisoners,’ Galiana said.
‘You’re planning to die fighting?’
‘No. And mass suicide doesn’t figure in our plans either. Neither will be necessary. By the time your brother reaches here, there won’t be anyone left in the nest.’
Clavain thought of the worms encircling the area; how small the chances were of reaching any kind of safety if it involved getting past them. ‘Secret tunnels under the worm zone, is that it? I hope you’re serious.’
‘I’m deadly serious,’ Galiana said. ‘And yes, there is a secret tunnel. The other children have already gone through it now. But it doesn’t lead under the worm zone.’
‘Where, then?’
‘Somewhere a lot further away.’
When they passed through the medical centre again it was empty, save for a few swan-necked robots patiently waiting for further casualties. They had left Felka behind tending the Wall, her hands a manic blur as she tried to slow the rate of collapse. Clavain had tried to make her come with them, but Galiana had told him he was wasting his time: that she would sooner die than be parted from the Wall.
‘You don’t understand,’ Galiana said. ‘You’re placing too much humanity behind her eyes. Keeping the Wall alive is the single most important fact of her universe - more important than love, pain, death - anything you or I would consider definitively human.’
‘Then what happens to her when the Wall dies?’
‘Her life ends,’ Galiana said.
Reluctantly he had left without her, the taste of shame bitter in his mouth. Rationally it made sense: without Felka’s help, the Wall would collapse much sooner and there was a good chance all their lives would end, not just that of the haunted girl. How deep would they have to go before they were safe from the suction of the escaping atmosphere? Would any part of the nest be safe?
The regions through which they were descending now were as cold and grey as any Clavain had seen. There were no entoptic generators buried in these walls to supply visual information to the implants Galiana had put in his head, and even her own aura of light was gone. They only met a few other Conjoiners, and they were all moving in the same general direction: down to the nest’s basement levels. This was unknown territory for Clavain.
Where was Galiana taking him?
‘If you had an escape route all along, why did you wait so long before sending the children through it?’
‘I told you, we couldn’t bring them to Transenlightenment too soon. The older they were, the better,’ Galiana said. ‘Now, though—’
‘There was no waiting any longer, was there?’
Eventually, they reached a chamber with the same echoing acoustics as the topside hangar. The chamber was dark except for a few pools of light, but in the shadows Clavain made out discarded excavation equipment and freight pallets; cranes and deactivated robots. The air smelled of ozone. Something was still going on there.
‘Is this the factory where you make the shuttles?’ Clavain said.
‘We manufactured parts of them here, yes,’ Galiana said, ‘but that was a side-industry.’
‘Of what?’
‘The tunnel, of course.’ Galiana made more lights come on. At the far end of the chamber - they were walking towards it - waited a series of cylindrical things with pointed ends, like huge bullets. They rested on rails, one after the other. The tip of the very first bullet was next to a dark hole in the wall. Clavain was about to say something when there was a sudden loud buzz and the first bullet slammed into the hole. The remaining three bullets eased slowly forward and halted. Conjoiners were waiting to board them.
He remembered what Galiana had said about no one being left behind.
‘What am I seeing here?’
‘A way out of the nest,’ Galiana said. ‘And a way off Mars, though I suppose you figured that part out for yourself.’
‘There is no way off Mars,’ Clavain said. ‘The Interdiction guarantees that. Haven’t you learned that with your shuttles?’
‘The shuttles were only ever a diversionary tactic,’ Galiana said. ‘They made your side think we were still striving to escape, whereas our true escape route was already fully operational.’
‘A pretty desperate diversion.’
‘Not really. I lied to you when I said we didn’t clone. We did - but only to produce braindead corpses. The shuttles were full of corpses before we ever launched them.’
For the first time since leaving Deimos, Clavain smiled, amused by the sheer obliquity of Galiana’s thinking.
‘Of course, the shuttles performed another function,’ she said. ‘They provoked your side into a direct attack against the nest.’
‘So this was deliberate all along?’
‘Yes. We needed to draw your side’s attention; to concentrate your military presence in low orbit, near the nest. Of course, we were hoping the offensive would come later than it did . . . but we reckoned without Warren’s conspiracy.’
‘Then you are planning something.’
‘Yes.’ The next bullet slammed into the wall, ozone crackling from its linear induction rails. Now only two remained. ‘We can talk later. There isn’t much time left.’ She projected an image into his visual field: the Wall, now veined by titanic fractures down half its length. ‘It’s collapsing.’
‘And Felka?’
‘She’s still trying to save it.’
He looked at the Conjoiners boarding the leading bullet; tried to imagine where they were going. Was it to any kind of sanctuary he might recognise - or to something so beyond his experience that it might as well be death? Did he have the nerve to find out? Perhaps. He had nothing to lose now, after all: he certainly could not return home. But if he was going to follow Galiana’s exodus, it could not be with the sense of shame he now felt in abandoning Felka.