He slows down and stops, but he's still staring straight ahead. There's a long blotch of damp on the side of his chest and I can smell alcohol.

'What you said,' I say. 'About your grandfather. Did you '

'Forget it.'

'So you didn't mean it?'

He looks at me. His expression is so hostile it's bewildering, as if the last few hours haven't happened. 'Just forget it.'

'But '

'It doesn't matter. Isn't that what you said? It doesn't matter. What difference does it make to anyone? They're both dead. And there's no evidence. No evidence that would there's no evidence. What are you going to do, run and tell the H. J. Martin Society?' He holds my gaze until I look away. Then he whistles tunelessly through his teeth, and adds, 'They're nutters anyway. Half of them think he's going to come back in England's hour of need, like King Arthur.'

I wait until I trust my voice not to crack. 'I'm not going to tell anyone. I just is it true?'

He takes a deep breath. 'Is it true that I believe it, or is it true?'

'Do you believe it? That your grandfather murdered H. J. Martin?'

He thinks for a moment. Then he says, 'Yes.'

We keep walking. I feel like the ground is sliding in the opposite direction, like a treadmill, so we're going slower than we should. The silence goes on and on, and things rustle and watch us from the bushes. It's too hot and too quiet. I can't think of anything to say. It's as if Oliver is somewhere else, and the gap's too big to shout across.

At the cracked bit of wall, he turns to me and says, 'You'd better go home.'

'My stuff's still over there.' I point towards the place where we sat to drink the whisky and Coke.

He stands aside without answering and gives me a businesslike hand to get over the wall. I want to stand on the other side and watch him climb over after me, but I trudge through the long grass and collect my biscuit tin and torch and books and empty plastic bottle. Oliver's shadow falls on my hands and I pick up his rucksack and pass it to him. He doesn't thank me.

I stand up with my arms full of stuff. He's got his rucksack over his shoulder. When I look at him, he glances away.

'You've got to stop coming here,' he says. 'I'm going to get someone to do something about that wall, and the railings. You won't be able to get in.'

I stare at him. 'What?'

'I'd better be off. Nice to've met you,' he says, picking a stalk of grass and rubbing it between his fingers. 'Apologise to your parents for me.'

'What? You're going now?' I say.

'Yeah.' He still won't meet my gaze. 'Thanks for the drink.'

I don't say anything. There's nothing I can say.

'Right then,' he says. 'Can you get over the wall with all that stuff or shall I help you with it?'

I want to throw it at him, bit by bit. I imagine hurling the biscuit tin last of all, how it would hit his head with a resounding clang. 'You're going,' I say, keeping my voice flat. 'Right now.'

'I should catch my train.'

'What time does it leave?'

'It ' He hesitates. 'I'll go down to the station and get the next one. They go every half-hour or so, don't they? Bibi, I should '

I don't know why, but the way he says my name goes straight to my gut, like a knife. It punctures something I didn't know was there.

I hear myself say, 'Don't go. Not right now. Please don't. Stay a bit longer. Stay until this evening. Please.'

'Bibi, I have to look, it wasn't a good idea to '

'Please. Please.'

Finally, he looks at me.

'You don't have to go right now,' I say. I can feel the biscuit tin slowly slipping out of my grasp. 'Please. It doesn't have to be horrible.'

'It's a complete disaster,' he says. 'I shouldn't be here. I should never have come.'

I can't think of anything else to say. 'Please.' My heart is beating so hard I can feel the fabric of my T-shirt trembling.

He looks down at me. He's squinting because of the sun, but his eyes are the colours of wood, amber and mahogany and green. He looks at me for so long I'm scared of what he can see in my face. Then he sighs and tilts his head back, defeated. 'I can't stay for long,' he says. 'I do, I really do have to go.'

I feel the air fill my lungs. 'I just ' I swallow. 'I just think you should buy me a drink, because it's your turn and I'm thirsty.'

He laughs: a helpless, abrupt laugh, like a release. 'Fine. Let's go to the pub.'

We look at each other. His eyes flicker, reading my face. Then he turns away.

As we walk I glance up at him. It's as if he notices my look, because he smiles and adds, 'I'm only buying you lemonade, mind.'

'Whisky and Coke,' I say. 'It's only fair.'

'Coke.'

'Shandy.'

'Oh, all right, shandy.' He reaches out and squeezes the back of my neck. 'Hey. How come I offer to buy you a drink and you negotiate? Honestly. The kids of today.'

I laugh. I walk very carefully, not making any sudden movements, because I don't think he realises that he's still got his hand on my neck and I don't want him to take it away. And he doesn't. He keeps it there, right up until we have to climb over the wall.

The beer garden of the Cloven Hoof is full of people all tourists, though, no one I know so I end up sitting on the wall under the horse chestnut tree while Oliver buys the drinks. The ground is covered with little scraps of brown flowers that stick to the soles of my shoes. I lean back against the trunk of the tree, looking up through the leaves. There's a wood pigeon somewhere, hooting and hooting as if it's trying to make everyone go away.

When Oliver comes back his face is wet, as if he's washed it, and he's carrying a tray with two tall glasses of water and a packet of crisps as well as our drinks. He balances it carefully on the wall and then levers himself up. He says, 'I seem to have done an awful lot of climbing on walls today. One of the waters is yours, so you don't get dehydrated.'

'Thanks.' I drink half of it in one go, and then reach for the shandy. Oliver does the same, and we clink our glasses. 'Cheers.'

For a moment it's like we're on holiday. Oliver lights a cigarette. I open the crisps I'm starving and realise I haven't had lunch.

We sit without talking until Oliver's flicked his cigarette away and I've finished the crisps. Then I close my eyes and lean back, half asleep, content.

'I'm not very good company,' he says, after a while.

I open my eyes and squint at him sideways. 'Aren't you?'

He hunches his shoulders, reaches for his cigarettes and then stops himself. 'I mean God, you must think I'm crazy. I think I'm crazy.'

'No. Mysterious. Enigmatic. A bit angst-ridden. A tall dark stranger with a past.' I make a face at him.

'I can't think straight. I don't know what I'm doing here.'

I pick up my glass and tap the rim against my teeth. 'Having a quiet civilised drink with a friend?'

He shakes his head at me, but he's smiling. 'Not what I meant, but '

I grin. Now we're here and not at Tyme's End, some of the tension that was in his face seems to have relaxed. And he didn't contradict me when I said friend . . .

He sits up straighter and finishes his beer. 'Enough about me. What are you doing here? Shouldn't you be with your own friends? Drinking cider on street corners or something? Isn't this a bit middle-aged?'

'None of my friends live in Falconhurst. Mum has to drive me to school, so . . . They all live miles away.'

He raises his eyebrows. 'What do you do in the holidays?'

'Sometimes I stay at their houses for a night. Or we meet in town, when Dad can give me a lift. Or I catch the train.' My voice has gone hard and defensive, although I don't know why. 'Anyway, I don't mind.'

'And the rest of the time? Don't you get lonely?'

'I like being on my own,' I say. 'I go to Tyme's End, and I read, and think, and '

He's staring at me. When he sees that I've noticed, he looks away, with a kind of gentle, anxious expression that makes me angrier.

'I'm fine,' I say. 'I'm fine. I like being on my own. I '

He doesn't answer.

'Anyway,' I say, 'it's not like there's anything I can do about it. So my friends all live miles away. It's not a big deal.'

He nods. I wish I hadn't mentioned Tyme's End. I finish my drink. I put the glass down next to his, but he's gazing at the ground and doesn't notice. He's drawing patterns in the withered horse chestnut blossoms with his foot.

He says, 'Tell me about your parents.'

It takes me a second to understand the words. 'What?'

'Your parents. Your real parents. What were they like?'

'I told you. My dad died, and my mum '

'No, I mean, what were they like?' He kicks gently at a wad of pale brown petals on the ground.

'My dad was a engineer. He went to Israel after he left university. He was called Alan. My mum was called Munira. She was sort of dumpy-looking. She was clever. My grandparents were really proud of her.' I shrug. 'What do you want to know?'

'Do you remember them?'

'I well, not my dad. And you know when you think you can remember things, but you've been told about them so often you don't know if you're remembering or imagining them?'

'Yes.'

'Well, I can picture my mum like that. I think I remember her playing with me. I can picture her bedroom. I stuffed a lampshade with tissues because it looked pretty and she was angry with me. We saw a house on fire once.' I kick my heels against the wall, slowly: right, left, right, left. 'I don't remember her dying.'

'Do you have photos and things?'

There's something strange in his voice, like the answer means a lot to him.

'A couple. Most of them are in photo albums and I can look at them, but I'm not allowed to take them out until I'm eighteen, in case I lose them.' There's a pause. I wish he'd say something. I can feel the matter-of-fact look on my face start to crack like varnish.

He nods. He reaches for his cigarettes again. I watch him take one out and light it. After he's lit it he turns his lighter over and over in his hands. His fingers leave smears on the silver.

'I've got a lot of . . . research,' I say. 'I call it that, anyway. It's stupid, but I haven't shown anyone, ever. Maps and pictures and things. Because ' I'm glad he's not looking at me. 'They're nice, Mum and Dad, I'm not being ungrateful, they didn't have to take me in, and but I don't belong here. It's not . . . mine.'

He tilts the lighter so that I can see his face, reflected. His eyes stare at me, pulled out of shape by a dent in the metal.

'I don't belong here,' I say again. I've never said it aloud before today. 'People look at me with Mum and Dad and Sam and they can see I'm not one of them. And here ' I look around at the tourists and the little kids playing on the grass. 'It feels like a foreign country.'

'You don't think you're English, because you weren't born here?'

'I know it's stupid. But I come from somewhere else. That makes a difference. You said yourself, the past is important. Well, my past is somewhere else.'

He turns his head to one side, frowning, as if he's listening to something a long way away.

I say, 'What's wrong? What did I say?'

'Nothing. You think the past is passed down in your blood or something.'

'Well '

'We inherit history. We don't have a choice about how we think, or who we are. It's already decided for us.'

'That wasn't what I '

'It's an interesting idea. Potentially racist, incidentally, but interesting.'

I twist to stare at him. 'Why?'

'Well, because if who you are comes from your parents and your ancestors, then you automatically have more in common with the people who come from the same genetic background.' His tone is intellectual, faintly amused. His accent is so English he sounds like someone from an old film. He catches my eye and laughs, but there's something uncomfortable in the way he's looking at me. 'I didn't say it was wrong. Necessarily.'

A silence.

I say, 'I wasn't saying '