The Arrows of Time

When her turn came at the counter she asked for two plain loaves; she’d discovered after the welcoming party that her gut no longer appreciated fresh spices. She carried the food to the corner farthest from the entrance, where an awkwardly placed cooling vent discouraged most diners. The present crowd left few enough alternatives for her choice not to seem too perverse.

She sat on the floor and ate slowly, her front eyes on her food, her rear gaze to the wall.

She was halfway through the second loaf when a man addressed her. ‘Did you drop these?’ Agata looked up. There were three coins on his outstretched palm; she squinted at them, memorised their value, then said, ‘No, they’re not mine.’

‘Sorry to have troubled you.’

Pio hadn’t told her how long she should wait, so as soon as she’d finished eating she left the hall and headed for the address indexed by the coins’ denominations. The area wasn’t familiar to her, but as she ascended the stairs towards the axis and then dragged herself along the corridor towards her destination, the smooth texture of the rock beneath her feet and the red tunnel of the moss-lit walls were enough to induce an ache of recognition. The death of every traveller save a handful of evacuees was beyond her power to imagine, but she’d come as close as anyone alive to feeling the absence of the mountain itself. If she needed a vision of the loss she was fighting to prevent, she could think of the Peerless retreating into the distance, shrinking to a dark speck against the stars and then vanishing.

Outside the door, she hesitated, but she’d have to trust Pio’s comrades to have chosen an appropriate level of precautions, and the innovation block to have kept the Council from automatically tracking everyone, everywhere. She knocked firmly, and after a few pauses the door swung open and a man invited her into the apartment.

‘My name’s Giacomo,’ he said.

‘I’m Agata.’ She closed the door behind her. ‘Can we talk freely?’

‘Absolutely,’ Giacomo assured her.

There was no point in prevaricating. ‘I want to help shut down the messaging system,’ she said. ‘We have a dozen and six small machines out on the slopes, capable of moving along the rock and flying for short distances. If you can tell us exactly where to send them, we can use them to occult the orthogonal stars for all of the channels.’

Giacomo hesitated before replying, but only as much as politeness required. He must have had years to consider her offer.

‘The system uses light from the entire orthogonal cluster,’ he said. ‘It’s not a matter of one star per channel. To shut it down, you’d need to blot out half the sky from twelve different vantage points.’

‘The entire cluster?’ Agata had always pictured a single star as the light source. When Medoro had first raised the idea with her, he’d started with a thought experiment where a distant object passed in front of a time-reversed star – and if the object had to be remote enough for the time the light spent in transit to be significant, it could hardly block out anything larger. But once you folded up the light path with mirrors, the same constraints no longer applied.

‘The optics gathers light from all directions visible from the base of the mountain,’ Giacomo explained. ‘Or sends it out, if you want to talk in terms of our arrow, but it’s easier for me to imagine the whole thing working backwards. All that each channel needs is a reliable light source that it can block or reveal with a shutter. Combining all the light from across the cluster makes the source brighter and more dependable.’

‘And less vulnerable to sabotage,’ Agata conceded. She’d convinced herself that the Councillors would be relying on secrecy, each one guarding the coordinates of their chosen star. Instead, they’d adopted a robust solution that could not be undermined merely by the revelation of a couple of numbers.

‘But your machines will still be very useful,’ Giacomo said encouragingly. ‘I can promise you that.’

‘How?’

‘They’ve been part of our plan for years. They won’t be able to block the channels with their presence alone, but they can still carry explosives to the sites where they’re needed.’

27

‘We’re not doing it!’ Agata declared angrily. ‘We’re not going to be accomplices to these murderers. We’ll have to find another way.’

Ramiro said, ‘There might not be another way.’

‘So now you’re happy to kill people?’ Agata stared at him in disgust.

‘We don’t know that there’ll be casualties.’ Ramiro paused, dismayed by the weakness of this disclaimer. But he pressed on. ‘If Giacomo’s group sets off a blast beside each light collector that’s just large enough to shatter it, that need not do a whole lot of damage further down.’

Agata was unmoved. ‘So you’ll trust the same fanatics who killed seven people in the camera workshop to be scrupulous now about sparing lives?’