the uprights. ‘You’re okay now, Prefect Ng. You took a bad bump on the head, but there’s no bleeding. We’ll get you checked as soon as we’re out of this.’
Through a curtain of pain, Thalia said, ‘I don’t remember. What happened?’
‘You were down in the basement, getting ready to set the timer on your whiphound.’
‘I was,’ Thalia said foggily. She had a groggy recollection that there had been some kind of problem with the whiphound, but the details refused to sharpen.
‘You banged your head on one of the struts, knocking yourself out.’
‘I banged my head?’
‘You were out cold. Citizen Parnasse carried you back up here on his own.’
The events began to come back to her. She remembered the second timing dial jamming, how she had come to the decision that she would have to detonate the whiphound manually. She remembered that awesome calm she had experienced, as if every trifling detail in her life had just been swept aside, leaving a breathtaking clarity of mind, as empty and full of possibility as the clear dawn sky. And then she remembered nothing at all, except waking up here.
‘Where is Parnasse?’
‘He went back down to set the timer,’ Redon said. ‘He said you’d shown him what to do.’
‘No—’ Thalia began.
‘We’re expecting him back any minute. He said he’d be able to tie himself down when he arrived.’
‘He isn’t coming back. There was a problem with the whiphound, with setting the five-minute fuse. I didn’t bang my head. Parnasse must have knocked me out.’
Redon looked puzzled. ‘Why would he have done that?’
‘Because I was going to set it off myself, while I was still down there. It was the only way. But he wouldn’t let me. He’s decided to do it himself.’
Comprehension came to Redon in horrified degrees. ‘You mean he’s going to die down there?’
‘He isn’t coming back up. I showed him how to set the whiphound. He knows exactly what to do.’
‘Someone has to go down there, tell him not to do it,’ Redon said. ‘He can’t kill himself to save us. He’s just a citizen, just one of us.’
‘When did he go?’
‘Quite a long time ago.’
‘He can’t set the fuse for longer than a hundred seconds. There’s no reason why he needs to wait that long, if he’s in place.’
‘You mean we could go any second?’
‘If the whiphound works. If the machines haven’t already broken through and stopped him.’ She knew she ought to feel gratitude, but instead she felt betrayed. ‘Damn him! He shouldn’t have brought me back up here. It wasted too much time!’
‘Maybe it wouldn’t be a bad idea if one of us—’
Redon never got to finish her sentence. Judging by the force of the blast, felt through Thalia’s spine as it transmitted itself through the fabric of the polling core sphere, the whiphound must have detonated at nearly its maximum theoretical yield. It had been a new unit, she remembered belatedly: she’d checked it out of the armoury only a couple of weeks ago. There would still have been a lot of energy left inside it, anxiously seeking release.
The sphere rocked appreciably: Thalia saw the landscape tilt and then settle again at its former angle. The blast had been very brief: a spike of intense sound followed by a few seconds of echoing repercussions. Now all was silent again. The sphere was still. The landscape outside was still.
‘It didn’t work,’ she said. ‘We’re not moving. It didn’t fucking work.’
‘Wait,’ Caillebot said quietly.
‘It didn’t work, Citizen. We’re not going anywhere. The blast wasn’t sufficient. I’ve failed you, used up our one chance.’
‘Wait,’ he said.
‘Something’s happening,’ Cuthbertson said. ‘I can hear it. It sounds like metal straining. Can’t you?’
‘We’re tilting,’ Redon said. ‘Look.’
Thalia craned her neck in time to see the white ball of the model polling core sphere roll across the floor, towards the window facing them.
From somewhere below there came a kind of twanging sound, as if the energy stored in a stretched spar had just been catastrophically released. The twanging sound was followed in quick succession by another, then a third, and then a volley of them too close together to count.
The tilt of the floor increased. Thalia felt her weight beginning to tug on the upright to which she was bound. The sphere must have been at ten or fifteen degrees to the horizontal already. She heard another series of metallic sounds: shearing and buckling noises, less like the failure of structural components than the cries of animals in distress.
The angle of the tilt reached twenty degrees and continued increasing.
‘We’re going over,’ she said. ‘It’s happening.’
Loose clothes and debris skittered across the floor, coming to rest along the curve of the outer wall. The architectural model slid noisily, then shattered itself to pieces. Thirty degrees, easy. Thalia felt an unpleasant tingling in her stomach. The landscape was tilting alarmingly. Through the windows, she could see aspects of the surrounding campus that had been obscured before. Suddenly it looked much further down than she had been imagining. Five hundred metres was a long way to fall. She remembered Caillebot’s reaction when she’d outlined the plan:
Maybe he’d been right all along.
Now the tilt was increasing faster. Forty degrees, then forty-five. Thalia’s arms felt as if they were being wrenched out of their sockets, but it was only the effect of her bodyweight so far. When the sphere started rolling, it was going to get much worse. Fifty degrees. The lower extremity of the stalk was beginning to come into view through the windows. In one brief glimpse she knew she’d been right about the war machines. They covered it like a black mould, reaching as high up the shaft as it was possible to see. They must have been very close to the sphere itself.
Something gave way. Thalia felt the sphere drop several metres, as if the upper part of the stalk had crumbled or subsided under the changing load. And then suddenly they were rolling, pitching down the side of the stalk, the angle of tilt exceeding ninety degrees and then continuing to climb. The sphere shook and roared. There was no time to analyse the situation, or even judge how far down the stalk they had rolled. There was only room in Thalia’s head for a single, simple thought:
She felt a momentary increase in the forces tugging at her body and judged that the sphere had reached the base of the stalk and changed its direction of roll from the vertical to the horizontal. She tried to time the duration of each roll, hoping to judge the distance they had travelled and detect some evidence that the sphere was slowing. But it was hopeless trying to concentrate on such matters.
‘I think,’ she heard Caillebot call out, between grunts of discomfort, ‘that we’ve cleared the perimeter.’
‘Really?’ Thalia called back, raising her voice above the juggernaut rumble of their progress.
‘We’re still rolling pretty fast. I hope we don’t just bounce right over the window band.’
It was a possibility neither Thalia nor Parnasse had considered. They’d guessed that the sphere would have enough momentum to reach the edge of the band, but they had never thought about it moving so fast that it would skim right across, moving too quickly to stress the window enough to break. Now Thalia realised that they were open to the awful possibility that the sphere might traverse the entire window band and come to a rolling halt on the next stretch of solid ground.
‘Can you see the band yet?’ she asked.
‘Yes,’ called out Meriel Redon. ‘I think I can. But something’s wrong.’
‘We’re coming in too fast?’
‘Not that. Shouldn’t we be rolling in a straight line?’
‘Yes,’ Thalia said. ‘Aren’t we?’
‘We seem to be curving. I can see the window band, but we’re approaching it obliquely.’
Thalia was confused and worried. They’d always assumed that the sphere would follow a straight course once it reached the base of the stalk, with only minor deviations caused by obstacles and friction. But now that she
