The Arrows of Time

‘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.