‘That’s brilliant,’ she breathed. ‘Why doesn’t it happen like that when I do it?’

Mark just grinned.

‘Yes, I know,’ she said ruefully. ‘Some of us can, and some of us can’t. They’re beautiful, Mark.’

He took a small memory stick from a drawer, connected it to the back, copied the pictures on to it, and gave it to her.

‘Just plug it into your machine when you get home,’ he said.

‘Thank you. I’ll give you this back at school.’

This wasn’t how she’d meant the conversation to go. She should be asking him why he kept vanishing and trying to understand him. But she felt that the key to understanding lay elsewhere. The friendly feeling they’d achieved would do him more good than all the talk in the world.

‘Will your father cut up rough about tonight?’ she asked gently. ‘I imagine he’s not easy to live with.’

‘He’s not so bad,’ Mark said unexpectedly. ‘He gets angry, but he’s always sorry afterwards.’

This was the last thing she had expected to hear.

‘He shouldn’t get mad at all,’ she said. ‘Why can’t he see that you’re unhappy?’

He considered this with an oddly adult expression.

‘He’s unhappy too,’ he said at last.

‘About your mother?’

‘I think so, but-there’s lots of other stuff that he can’t talk about. I used to hear him and Mum rowing-terrible things-she said he had something dark inside him, and why couldn’t he talk about it? But he said talking wouldn’t change anything, and walked out. I was watching from the stairs and I saw his face. I thought it would look angry, but it didn’t. Just terribly sad.’

‘Did he know you saw him?’

Mark shook his head. ‘He’d have hated that. He doesn’t like people to know how he feels.’

He fell silent. Then he said unexpectedly, ‘I keep wishing I could help him.’

She gave him a quick look of surprise, asking, ‘Shouldn’t he be helping you?’