The Arrows of Time: Orthogonal Book Three (47 page)

‘Another way to cause the shutdown.’

‘And if you find one, will the saboteurs call off their plans?’

‘Probably not,’ Agata admitted. ‘Even if I could persuade Ramiro and Tarquinia, I doubt they’re in control any more.’

Serena said, ‘So you’re saying that these saboteurs might be the greatest threat. But what would happen if we managed to stop them?’

‘Something still has to cause the disruption,’ Agata replied. ‘A meteor, or a mob.’

‘There are dozens of us ready to protect the mountain,’ Serena avowed. ‘But we might not be enough to cause the disruption by sheer force of numbers, let alone stage some
second action against the saboteurs as well.’

They’d almost come full circle back to the apartment, but Agata couldn’t face the piles of unread books again. She wasn’t going to transform herself into Medoro in the next few
bells. ‘We had a time-reversed camera on the
Surveyor
for years,’ she lamented. ‘I could have spent all my free time experimenting on it, if I’d known how useful
that would be.’

Serena was amused. ‘The rest of the crew might not have been too happy if you’d destroyed it.’

‘After we’d left Esilio it wouldn’t have mattered. But we certainly took care of it until then.’ Agata stopped and stood clutching the guide rope, thinking about the
landing. ‘Protecting it from too much exposure.’

‘You mean not pointing it at Esilio’s sun?’ Serena frowned. ‘Though wouldn’t that have . . . brought it back to normal, if it had arrived burnt out?’

‘Protecting it from too much ordinary light as well,’ Agata said. ‘Intense light would have damaged it: scatter from our engines, say.’

‘So you want to steal the
Surveyor
and aim its engines at the base of the mountain?’ Serena joked.

Agata said, ‘No. But a big enough explosion above the base should have the same effect . . . or twelve smaller ones might do it.’

Serena understood. ‘You want to repurpose the saboteurs’ bombs? Use the flash but not the bang?’

‘Why not? The collectors gather light from all directions – and they can’t discriminate between ordinary light and time-reversed light. If we can shift the explosions far
enough away from the surface that there’s no risk of them breaching the tubes, they could still be the cause of the disruption. They don’t even need to damage the cameras permanently
– they just have to overwhelm the photonics long enough for the time-reversed light that’s in transit to be lost.’ The original plan for the occulters had been to blind each
channel to a single star, but the design that made that impossible rendered this new plan far less demanding: it didn’t matter where in the sky the explosions appeared. The collectors would
funnel all the photons in and dazzle the cameras, regardless.

Serena said, ‘What if there’s a sensor that can bring down a shutter if the ambient light gets too bright? I mean, the light that’s meant to do this damage will be bouncing
back and forth between the mirrors before it gets to the camera. There’ll be plenty of time for news of the danger to reach the camera by a shorter route.’

She was right, Agata realised. But it might not matter. ‘They can bring down a shutter to protect the camera from permanent damage . . . but that shutter will block the time-reversed
light, too. So it will all come down to the timing: whether the flash from the explosions forces the shutter to close for so long that the signal is lost.’

Serena was quiet for a moment. ‘So how do we divert the saboteurs’ bombs? Go out there and physically move them?’

‘Maybe,’ Agata replied. ‘But I don’t know how we can get out undetected.’

Serena was incredulous. ‘You think the Council will try to stop us
protecting the mountain
?’

‘Not as such – but if we’re going to tell them our plan, they’ll have known about it for the last three years. So why wouldn’t they have modified their own defences
at the base to take account of what we tell them about the occulters and the explosives?’

Serena said, ‘Because we don’t tell them. Because we’re afraid that they’d find a way to prevent the explosions from causing the disruption – which would bring us
back to a meteor as the cause.’ She put a hand over her eyes and massaged her temples. ‘Just when I’d stopped getting messages from myself, the future finds a new way to order me
around.’

‘Has it told you how to get into the void unseen? Or do some of your army of waking sleepers happen to be airlock guards?’

‘No airlock guards,’ Serena replied, ‘but we have technicians capable of splicing photonic cables and disabling sensors.’

‘That’s not enough,’ Agata said ruefully. ‘There’ll be people at all the airlocks, from now to the disruption.’

Serena hummed angrily. ‘So do you believe we’re going to do this, or do you think we’re going to cower in our rooms and wait for whatever unfolds?’

‘I don’t know.’ Agata hadn’t been able to bring herself to reveal what Ramiro had told her about the inscription. The only certainty they had now was the disruption;
there was no promise of any kind of triumph to follow.

‘Are you still working in the cooling tunnels?’ Serena asked.

‘No.’

‘But you’re familiar with the whole system?’

‘I’ve done the induction – it was fairly detailed. Why?’

Serena said, ‘Cooling air
leaves the mountain
– and there won’t be people guarding every vent. If my technician friends can disable the sensors, we can go out with the
air and start looking for these bombs.’

Agata began buzzing softly. ‘You think they’ll let a mob of saboteurs congregate at an air vent? There are cameras in every corridor, there are people watching every move we
make.’

‘Maybe your moves,’ Serena conceded. ‘The mere fact that you were on the
Surveyor
with the anti-messager Ramiro taints you a little. But who am I? Who are my friends?
There aren’t enough people in the entire security department to watch everyone, and the software never got smart enough to take over the job. We’re not saboteurs, we’re not known
dissidents. While they’re watching the usual suspects, all we have to do is avoid setting off the kind of alarms that can’t be ignored.’

In Gineto’s apartment, Vala spent a chime scrupulously copying Agata’s posture and learning to mimic her gait.

‘No one would mistake our faces,’ Vala admitted, ‘but if I hold this box of books on my shoulder to obscure my face from the camera . . .’ She demonstrated.

Agata had carried Medoro’s real books home in more or less the same way; a second instalment need not attract suspicion. She handed Vala the key to her apartment. ‘Happy
reading.’

She waited with Serena and Gineto, practising her imitation of Vala but hoping that no one would even be watching the camera feeds. Let them all be busy following Ramiro and Tarquinia.

Serena checked the clock on her belt. ‘Time to go.’

Gineto said, ‘Good luck.’

Agata followed Serena out of the apartment, trying to appear suitably motherly: mildly affectionate but mostly aloof. Vala had always seemed bemused that two lumps of flesh shed from her body
had grown into fully functioning creatures, with no further intervention on her part. The corridor wasn’t too busy, so Serena took the adjoining rope, never concealing Agata entirely from the
cameras they passed, but often obscuring part of the view. Anyone with access to the feeds would be able to reconstruct every party’s true movements easily enough, in retrospect – or
long before the event, if the information was recognised as important enough to send back – so their not being caught out now would be largely contingent on their not being caught out later.
From their position of ignorance, success and failure seemed balanced on a knife edge, but from a cosmic point of view the two slabs of self-consistent events had been utterly distinct for at least
the last three years.

As they drew nearer to the utility shaft, Agata could see a camera gazing straight down at the entrance portal. They hung back, and Serena glanced at her clock. ‘Where are they?’ she
muttered. A moment later Agata heard a group of people approaching, talking and buzzing.

‘Now,’ Serena whispered. They advanced together. There were a dozen people coming the other way, spread out between the two guide ropes. Some of them, politely, tried to shift ropes
to let Serena and Agata pass, but they were packed too close together along both ropes for them to all fit on either one. As the impasse clumsily sorted itself out, two women who looked like mother
and daughter managed to break out of the throng and move away. Agata followed Serena down into the shaft and pulled the portal cover closed behind her. If the security sensors here hadn’t
been dealt with, they wouldn’t be the first ones to trigger them: the portal’s lock had been snapped a few bells before, and most of the team was meant to have come through before
them.

As they descended the ladder in the red-tinged gloom, Agata could hear the muffled hiss of gas in the tunnel beside them. No one came here on regular cleaning shifts; the warm air was inimical
to moss.

When they arrived at the bottom of the shaft the darkness was impenetrable. Serena said quietly, ‘It’s us,’ and someone switched on a coherer. Agata squinted into the glare and
counted two dozen and nine figures squeezed around them, already wearing their corsets, cooling bags and jetpacks. Many of them had never used the jetpacks; they should all have had one-on-one
briefings earlier from their more experienced friends, but it was Agata’s job now to go through the safety checks and remind them of everything they’d forgotten.

‘If you get into trouble,’ she began, climbing two steps back up the ladder to make herself visible to everyone, ‘just draw a stop line: a straight horizontal line across your
chest.’ She demonstrated. ‘The rock will still be moving below you, but don’t let that confuse you: the pack will bring you to a halt relative to the mountain’s axis, so you
won’t go flying off into the void.’

There was no time for more than the basics, but if they could retain it, it ought to keep them alive. Agata put on her own equipment.

‘Does everyone understand what we need to do with the occulters?’ The protocol she’d written had been copied discreetly from skin to skin, and some of the volunteers would not
have received it until they’d reached this assembly point. In a perfect world they would have rehearsed the manoeuvre daily for a stint or two, but at least the jetpacks would handle most of
the navigation.

‘Can the machines drill into our bodies?’ a young man asked anxiously.

‘Not intentionally,’ Agata assured him. ‘They’re not that sophisticated; they have no defensive strategies as such. The only danger is if they’re so confused that
they mistake you for rock, but if you get out of their way they won’t pursue you.’

Serena passed Agata a helmet. They were aiming not to use the links; this would probably be their last chance to talk until they were back in the mountain again.

‘Happy Travellers’ Day,’ Serena said.

‘Happy Travellers’ Day,’ Agata replied. She put on her helmet and turned towards the maintenance hatch.

A succession of shutters sealed off portions of the final length of the cooling tunnel, opening in sequence to allow air to pass from chamber to chamber at ever lower pressures until it was
expelled into the void. The maintenance hatch wasn’t meant to open unless the whole cycle had been stopped and all the chambers had reached the ambient pressure of the mountain’s
interior, but Serena’s technician friends had managed to fake the sensor data to convince the hatch that it was safe to operate. The only catch was that it had been too complicated to try to
lock it against any real part of the cycle. It would be up to each person exiting to synchronise their access with a time when the shutter below them wasn’t open to the void.

Agata pressed her helmet to the hatch and listened to the sequence of clanks and hisses until the rhythm was embedded in her mind. The last time she’d dealt with machinery in the tunnels
it hadn’t ended well, but at least she’d had the timing right.

She slid the hatch open. Air blew in from behind her, but it only took a flicker for the pressure to equalise. She climbed into the tunnel and braced herself against the walls with her hands and
feet. Serena closed the hatch behind her.

Agata waited in the dark, mentally composed but still viscerally terrified: there was absolutely nothing about the situation that her body found acceptable. She heard the creaking of the
shutters above her and the sibilance of expanding gas drawing nearer.

A span from her head, the rotating disc of the shutter above her finally swung its aperture around to coincide with the tunnel. Agata felt the air rising up across her cooling bag, moving the
opposite way to the usual cycle now that she’d wrecked the pressure gradient. But the sensors had been numbed – the anomaly would pass unnoticed.

When the shutter closed there was nothing to feel, and in the perfect darkness no way to be sure that it had happened. But then the exiting wind rustled the fabric on her limbs and starlight
entered the tunnel from below. Agata didn’t look down for confirmation; she just brought her limbs together and let herself fall.

Half a dozen strides from the outlet she drew a circle on her chest and the jetpack eased her to a halt, supporting her as she followed the rotation of the
Peerless
. She sketched an
upwards arrow and ascended, until a safety handle set into the rock for maintenance workers came within reach. Wide-field cameras on the slopes monitored the space around the mountain, with their
feeds analysed automatically to detect anyone in trouble falling away into the void, but as long as the team remained close to the hull they’d be out of view.

Agata waited for Serena to emerge, and for two more of their companions to join them. They couldn’t stay to watch the whole team exit; there were only four handles, and hovering would
waste too much air. Agata gestured to the others and they set off for the base.

The starlit slopes turned beneath them, the pale brown calmstone sliding past ever faster as they moved further from the axis, making their straight-line trajectories seem like giddy spirals.
Agata kept watch for sudden changes in the topography ahead; the jetpacks knew the basic shape and motion of the
Peerless
, but they carried neither detailed surface maps nor proximity
sensors. No one had ever intended the wearers to skim the slopes at high speeds, so if she slammed into an unexpected rise she’d only have her failing eyesight to blame.