‘Who did you think it was?’ she risked saying.

‘What?’

‘I need to know how much you can remember. It’ll tell me how serious your concussion is.’

‘I did several laps and everything was all right. But then-’ He took a long, shaking breath. ‘Why did you come onto the track?’

‘I didn’t.’

‘But you did. You were walking straight towards me, and your hair was blowing in the wind. I could have ridden right over you, but you didn’t seem to realise that. You were smiling-like the time-’

His breathing was becoming laboured and she went to him quickly, trying to soothe him.

‘It wasn’t me. Truly. It was the speed that confused you, and that visor. You couldn’t have seen anything properly. Just an illusion-someone who wasn’t really there.’

‘But-she was there,’ he whispered. ‘I saw her-’

‘You couldn’t have. It’s impossible.’

‘How can you be sure?’

‘Because-’Suddenly realising that she was straying onto a dangerous path, she checked herself. At this moment she couldn’t tell him why she was sure he would never see Sapphire again. The truth would crush him.

‘Because if there had been anyone on the track you’d have hit them,’ she said.

‘You can’t hit a ghost,’ he said wearily. ‘Do you believe in ghosts?’

‘Yes,’ she murmured, saying it almost against her will. ‘I try not to, but sometimes people just won’t let go-no matter what you do, they’re always with you.’

‘So you know that too?’

‘Yes,’ she said quietly. ‘I know that too. Go to sleep now.’

He moved his hand forward and back, then sideways, as though searching for something. She reached out and took his hand, feeling the tension in it.

‘It’s going to be all right,’ she said.

Some corner of his mind-the part of him that argued with everything-wanted to demand how she could be so sure. But the argument retreated before the reassurance of her clasp. His thoughts were confused.