‘You won’t get away,’ Casey said.

Clio glanced back at Casey. ‘No?’ she raised an eyebrow. ‘I’m the one who won’t get away?’

‘It doesn’t matter what you do to me,’ said Casey. ‘They’ll get you.’

‘We’ll see.’

Clio kicked the horse, urging it into a trot. Casey was hauled along, fish on a line, battling to keep up as her wrists bruised on the cuffs.

‘Let me go,’ she screamed.

The horse trotted faster, yanking Casey along. Any moment, she would slip and fall, and be dragged helpless over the rocks and the branches.

‘Please,’ Casey heard herself beg. ‘Please don’t do this.’

‘Take my deal, Casey.’

Casey struggled through the leaves. ‘I can’t.’

They had reached the edge of the woods now. Casey stared around and realised that they were on the edge of the airstrip. The narrow strip of grass – clipped short and rolled – disappeared into the distance. To the left, Casey could see the collection of buildings that made up the home farm, and a few hundred yards away a small plane.

‘Last chance,’ said Clio. ‘Last chance, Casey.’

‘No,’ Casey said.

Clio glanced around at Casey, her mouth a thin line, and kicked her horse hard.

The horse half-reared and leapt forward. For a split second, Casey saw the chain whip through the air, before the jolt hit her, almost yanking her shoulders out of their sockets. Casey was torn through the air, crashing face-first down onto the grass.

The horse galloped along the runway, whiplashing Casey in its wake. Casey screamed as a blazing pain flashed down her arms. She tried to roll onto her side, in a hopeless effort to save her face, her teeth, her eyes. The world skidded past, a blur of grass and sky. She couldn’t breathe, couldn’t see, couldn’t think. The pain swallowed her. She hit a clump of grass, bounced in the air, slammed back down.

‘Stop,’ screamed Casey. ‘Please stop.’

‘Will you?’ shouted Clio.

Casey couldn’t answer, was battling to stay alive.

‘Will you?’ The witch’s scream.

‘No,’ Casey gasped.

Clio jerked the horse, pulling him to a halt.

Casey lay on the ground, her arms contorted, her clothes torn. Her limbs were covered with cuts and bruises, and blood poured from her forehead.

Clio shrugged. ‘At least I waited until we reached the grass.’

Almost meditatively, Clio slid off the horse, unclipping the chain from the saddle. Casey was gasping for breath, trying to move her arms.

‘So you won’t do it,’ Clio said, almost to herself.

There was a long pause.

‘No,’ Casey muttered. ‘No, I won’t.’

‘But why not?’ There was frustration in Clio’s voice. ‘How do you decide, Casey? You? What gives you the right to make these decisions?’ She jerked at the chain.

‘I don’t know,’ Casey whispered, almost to herself.

Clio stared at her a long time.

‘Fine,’ she said. ‘Stand up.’