‘Ramiro?’

He looked up; Tarquinia had reappeared on the navigation screen.

‘What’s happening?’ he asked, surprised that she’d have anything more to report so soon.

‘Don’t panic,’ she said. ‘The spin-down’s going perfectly.’

‘But?’

‘I just saw the latest snapshot of the halo.’

Ramiro’s anxiety deepened. The navigators used ultraviolet images of the region around the Object as a way of measuring the density of interstellar gas, traces of which could be seen being annihilated as it struck the orthogonal asteroid’s dust halo.

Tarquinia read the look on his face and buzzed softly. ‘The gas is as rarefied as ever; the corridor should still be safe to traverse. But there was something unexpected on the image. I think it was a gnat moving away from the Station.’

Ramiro struggled to make sense of this claim. ‘I heard there was a gnat left behind; the last shift didn’t have enough pilots to fly them all back. It should have been tied up, but I suppose it could have sprouted some kind of air leak that pushed it away—’

‘I don’t mean drifting,’ Tarquinia interjected. ‘It was firing its engines. Some of the flare came our way – that’s the only reason it showed up on the snapshot.’

‘But the Station’s empty. Everyone’s been evacuated.’

Tarquinia knew what she’d seen. ‘Do you think someone could have automated the gnat?’ she asked. ‘To start flying on its own, after they’d left the Station?’

‘It’s possible,’ Ramiro conceded. ‘But why would they?’

‘I have no idea. But it’s either that, or someone’s managed to stay behind.’

‘What are you suggesting? Some disappointed voters from Pio’s faction have decided that they’re going to get their way after all . . . at the Station?’ Ramiro didn’t know whether he should be amused or horrified. The ambition was comical, but if there really were holdouts who’d concluded that the safest life they could make for their children lay in an abandoned research habitat, there’d be nothing funny when they starved to death.

‘This image shows a gnat using its engines,’ Tarquinia replied. ‘I’m not going to try to guess if there are people inside, let alone what their motives could be.’

‘Do you want me to chase down the Councillors?’ Ramiro didn’t know whose job it had been to ensure that every last traveller was inside the Peerless before the spin-down commenced, but he was glad it fell entirely outside his own domain.

Tarquinia said, ‘You’d better do that.’

Ramiro loosened his harness. ‘If we had cameras in all the corridors,’ he mused, ‘and programs for recognising invariant anatomy . . .’

‘We could have done an automated census before starting up the engines?’ Tarquinia suggested.

‘Ah, good idea.’ Ramiro hadn’t been thinking on quite that scale. ‘I was just picturing a way of getting messages to people when they were wandering around the mountain.’ But Greta and her guests would not have gone far. ‘Are you certain this isn’t a false alarm?’

‘No,’ Tarquinia admitted. ‘But if we fire the main engines and there are people left behind, do you want to be the one who takes responsibility?’