The Arrows of Time: Orthogonal Book Three (44 page)

She reached the end of her allotted segment of the tunnel with almost a bell to spare, then she turned and raced back towards the start. The hard part was doing it quietly, keeping her feet low
and lengthening her strides instead of breaking into a run. People were used to hearing workers in the tunnels, but the sound of outright sprinting might attract attention.

Light from the open hatch marked her entry point, but when she arrived at the ladder she slid the hatch closed above her and waited for her eyes to readapt to the dark. A couple of strides
down-axis from the hatch, a hardstone grille covered the width of the tunnel. Peering between the bars she saw nothing: no flashes from the coherer of another tunnel worker burning off moss. Agata
hadn’t quizzed Celia about anyone else’s shifts, but she’d chosen the latest of the time slots on offer. It was possible that right now there was no one at all between her and the
cooling chamber.

She lay on the floor of the tunnel and rearranged herself so that she could reach down her throat and retrieve the small bundle of tools she’d swallowed. The rags they were wrapped in were
covered with clumps of food and digestive resin; she shuddered but managed to avoid emitting a hum of revulsion as she flicked her hand clean.

By touch, Agata confirmed what she’d guessed by sight when the grille had been illuminated: the bars really were embedded in the wall, continuing right into the surrounding stone. The
masons must have drilled one hole straight, but created a whole triangular cavity at the opposite point, allowing a rod that was too long to fit directly across the tunnel to be inserted at an
angle and then made true. They would have packed the cavity with sand and adhesive, and over time it would have set into something almost as strong as the surrounding calmstone. But though the bars
themselves were close to unbreakable, calmstone was just calmstone. Agata put the point of her hand drill against the wall beside the longest of the bars and set to work enlarging the hole that
contained it.

By the end of her shift she’d made slots that allowed her to remove and replace three of the bars at will. Two more, and she’d be able to squeeze through.

Agata packed up her tools and forced herself to swallow them again. Beyond the half-disassembled grille and the last segment of the tunnel, there’d be another grille just like it guarding
the outlet from the chamber itself. She’d need more time to transit that segment, but the task no longer seemed impossible.

Agata ground the roots with the mortar and pestle she normally used for spices, feeling like some kind of demented kitchen alchemist. The flowers she’d cut up were all
decorative species that had been planted around the beds of travellers for generations, in a relic of the old folk belief that their petals’ light had health-giving properties. She had never
gone in for the custom herself, but at the garden no one had questioned her. The assistant had invited her to pick whatever she liked.

Every plant root contained substances that bound to a range of minerals. Over the generations, chemists had painstakingly tabulated their properties, species by species, and the appendices to
Agata’s school chemistry textbooks were full of such quaint pre-photonic compendia.

The effect she was hoping for was not dramatic; she didn’t need a liberator to set the sunstone in the cooling chamber on fire. All she had to do was ‘poison’ a large enough
portion of the surface of the rock. The size of the air particles that the sunstone produced was sensitive to the amount of time the decomposing agent spent in contact with it; if she could weaken
the agent’s binding, some lighter air than normal would be produced. The total volume didn’t have to be enormous; the giant centrifuge of the
Peerless
itself would separate out
the less massive component, concentrating it preferentially around the axis.

If she could get enough disruptor into the cooling chamber, the next step would be verification. She would need to be able to quantify the effect of her intervention on the refractive index of
the air near the axis, not least to be able to convince Ramiro and Tarquinia to abandon their own efforts. The shift ought to be measurable in principle, but it would require specialised,
high-precision instruments. Agata had no idea how she could get her hands on equipment like that without attracting attention – but she was sure that, like every other aspect of the plan, if
she remained resolute it would fall into place.

‘You get keener every day,’ Celia observed. ‘I can move you to an earlier shift if you like.’

‘No, this is perfect.’ Agata wasn’t sure how much explanation her early starts required. ‘I just have trouble planning the journey sometimes; if I’m not as
energetic it can take me a few more lapses to get here, but if there’s any doubt I’d rather make sure I won’t be late.’

‘Hmm.’ Celia didn’t care. ‘Any new thoughts about the disruption?’

‘I’m still optimistic,’ Agata replied cautiously.

‘You’ve seen the ancestors’ writing,’ Celia acknowledged. ‘Of course that makes you hopeful. But they didn’t tell you how many of us survive.’

‘But nor did they mention a great tragedy,’ Agata replied. ‘They just offered their thanks. If the mountain had been shattered, you’d think they would have aimed for a
higher level of solemnity.’

Celia was amused. ‘Six generations on? It will all be ancient history by then. They’ll carve their memorial on Esilio and some politician will make an empty speech.’ She handed
Agata her tool belt and access key. ‘No one will know what our lives were really like, and no one will care.’

Agata said, ‘Perhaps.’

Agata forced herself to complete a full sweep of the tunnel, burning off every visible speck of moss. But as she raced back towards the site of her real work, when she noticed
one faint red smudge that she’d missed she did not stop to pull her coherer from her belt.

She paused to disassemble the centre of the first grille, then she slipped through and continued down the tunnel. Her fellow worker who came here on an earlier shift had left a few mossy smudges
of her own; no one was perfect. Agata reached the second grille with almost a bell to spare. She reached into her gut and pulled out her tools. The package was tied by a string to her first
canister of disruptor.

Working on the grille in utter blackness was pure instinct for her now; her fingers gauged the narrow trench left by her previous assault and guided the drill to the right location with no
intervening thought. Between bars, she only stopped to check the clock on her belt.

When she’d eased the fifth bar out and laid it on the floor of the tunnel beside her, she hesitated. Maybe there were invisible defences around the outlet – vibration sensors and
high-powered coherers. Before the bombing that would have been unlikely, but anything was possible now.

Agata reached through the grille and sent one of the bars skidding towards the outlet. No weapon’s flash broke the darkness. She only had a few chimes left in her shift, and four days
before her most optimistic deadline for starting the diffusion. If there ever was a time to take courage and tell herself she was untouchable, wrapped in the arms of the ancestors, this was it. She
crawled through the broken grille.

She’d thought she’d grown accustomed to the blasts of chilly air, but as she crossed the last few strides each wave of pressure felt like a physical assault. She switched on her
coherer at the lowest possible brightness and squinted into the machinery where the tunnel began.

In the chamber below her, the pressure of the newly formed gas was increasing, forcing the piston up along the outlet shaft. She could see the great polished stone cylinder rising now, the side
of it completely blocking the tunnel, its motion only visible from flaws and scratches rushing by.

Then it cleared the mouth of the tunnel, and the cold air from the chamber came rushing out. Agata felt every hardened patch of wizened skin on her body forced into the flesh beneath, with the
chill only sharpening the sensation.

As the pressure driving it plummeted, the piston stopped ascending and came hurtling down. Agata had known the rhythm of the full cycle from the first day she’d crawled into the tunnel,
but what mattered now was the exact time the outlet shaft was exposed. She crouched before the piston, utterly attentive, letting the process imprint itself on her, binding every visual and tactile
cue into a single act of perception.

She closed her eyes, waited for the moment, opened them: and there it was, the bottom of the piston rising up. She couldn’t lose it now, she couldn’t get it wrong.

Agata drew the canister of disruptor out of her tool belt, and unscrewed the lid to the point where one more quarter-turn would free it. A single knock would spill the contents, but mere passage
through the air would not; she’d tested that a dozen times.

She closed her eyes, waited, then opened them. She hadn’t lost the rhythm. Every muscle in her body knew what to do, and when.

The piston plunged, the pressure rose. Agata waited. The piston ascended.

As the piston rose above the mouth of the tunnel, she threw the canister. It entered the shaft and disappeared. She heard no sound from the impact, but she hadn’t expected one; the bottom
of the chamber would be far below, and the canister might yet be spinning in mid-air, still caught in the updraught.

The piston crashed down again, closing the mouth of the tunnel. Agata closed her eyes, overcome with relief. She had four more days; she could prepare and deliver at least four more doses. All
her numbers were approximations and guesswork, but unless she had wildly miscalculated, that total would at least give her a chance.

The air burst out from the chamber once more; Agata opened her eyes to welcome it. A trace of fine grit stung her eyes, then something clattered loudly across the tunnel floor.

The canister came to a halt beside her. She stared down at the rejected gift. If it had travelled all the way into the expanse of the chamber, it was very unlikely to have entered the shaft
again.

There had to be a grille or baffle of some kind at the bottom of the shaft – below the piston’s lowest point, or the canister would have been crushed into powder. Some of the
disruptor would surely have ended up inside the chamber, but the grit blown back at her must have been the rest.

Agata touched the clock on her belt; she needed to start moving immediately, or she’d be so late for her end of shift that Celia would send in a search party. She gathered up her tools and
the lidless canister and forced them back into their hiding place.

She had four days left, and a barrier at the bottom of a giant, pounding piston that would reject most of what she threw into the shaft.

But as she retreated along the tunnel, she finally understood where the plan was leading her. She could dive under the piston, survive the landing on the barrier, and – if the low point of
the piston’s motion was high enough – remain there unharmed long enough to deliver the disruptor into the chamber by hand. That much was possible.

But once she was down there, there would be no way out.

‘Have you checked the horizon lately?’ Tarquinia asked Ramiro, following him into the apartment.

‘I think it’s still about a bell away,’ he said. There was no official cut-off point, but there was a public site where people had posted the times of origin of all the
messages they’d received from the last few days before the disruption. Ramiro harnessed himself to the desk beside his console and brought up the file.

‘No change,’ he reported. ‘Do you want to try out the system while you still have a chance?’

Tarquinia hummed with mock regret. ‘Too late. Let the messagers who want the bandwidth have it; I’m not going to steal it from them for a cheap thrill.’

‘Then why do you care about the timing?’

‘This is the start of freedom,’ she said. ‘The Councillors might know everything they’re going to do for the next three days, but most people will have nothing
proscribing their actions.’

Ramiro wasn’t expecting an uprising. ‘It’s going to take more than three days for the effects of the last three years to fade. And if there was going to be public unrest, I
think the Council’s own bulletins would have mentioned it.’ Censoring bad news wouldn’t change anything, and once the omission came to light it would only undermine the
government’s credibility.

He took the link from its hiding place under the desk and plugged it into the console.

The occulters were approaching the bottom of the mountain. Having them crawl over the sharp edge that divided the slopes from the base would have been insanely ambitious, so the machines had
been instructed to fly from one surface to the other, keeping as low as possible but sparing themselves the most difficult terrain.

Centrifugal gravity turned the base of the mountain into a sheer vertical wall. The cargo hooked to the occulters’ arms would hang down over them, applying a torque that would try to peel
them off the rock, and increasing the risk of the connecting strings becoming tangled in the clockwork. Ramiro had programmed adjustments to the depth and angle of the drills that he hoped would
minimise the problems, but it was all untested; there’d been no reason back on the
Surveyor
to rehearse for this strange asymmetric loading. He found it hard not to resent
Giacomo’s group for failing to devise a better solution when they’d had three years’ warning, but then the innovation block wasn’t an imaginary disease that people invoked
just to excuse their laziness. Agata’s long silence since she’d set out to overcome it proved just how pernicious it must be.

A short burst of data appeared on the console. Tarquinia chirped. ‘Number one’s made the jump!’

Ramiro waited for the next report, then scrutinised the figures. ‘It’s clinging on, and it hasn’t jammed.’ He wasn’t satisfied yet; it was still possible that the
strings would become progressively twisted. The occulter rotated its body in opposite directions with each step, so all things being equal it ought to unwind as much it entwined, but he could
imagine some configurations of the strings interfering with the process and favouring one direction.