I felt damp and cross. A bit of grit in my shoe pressed against the ball of my foot; my scalp itched under my head and my neck itched and my hands sweated and my nose felt cold. Why couldn't she just listen and nod and hold my hand?

'I think you've turned this into a self-consuming obsession. Solve this puzzle, and another one will appear. You want some ultimate, complete meaning to a messy tragedy. You've lost your wit.'

'Wits.'

'Wit. You're getting boring. Can't you let it go?' You're getting boring. Can't you let it go?'

I climbed over a stile, staining my palms green with slimy lichen.

'I want to. I thought it would all be over, that I was coming here to end the whole foul business and this'll sound stupid to find Natalie again. She'd become like a jigsaw puzzle or something, and the only bits of her character I thought about were the bits that made sense of her murder. And then the other day I had this really clear image of her, it was as if I could reach out and touch her. I did love her, you know; she was my first best friend. So I needed to come and say goodbye to the real her, in the place where she last was. But I feel so... so strange, somehow. It's as if I know something more, but I can't get at it. It might be boring but... oh s.h.i.t, lateral thinking, that's what I need. I feel like I'm going mad.'

Kim said nothing. We walked down the hill to the car.

'You do still want to stay for the rest of the weekend, don't you?' asked Kim, as we drove back to the hotel.

'Yes, of course.' Then : 'Well, actually, Kim, I don't think I can. I feel all restless now. I'm really sorry, but can we drive back tonight?'

Kim looked grim.

'It was a bit of a long drive for one late night, and a single soggy walk.'

'I know. I just wouldn't be very good company.' I opened a window and lit a cigarette. 'Unfinished business and all that. It's like that mad woman said to me : it's not over yet.'

'As usual today, I haven't the faintest idea what you're talking about. However' Kim reached out a hand and touched me briefly on the shoulder 'let's not bicker. I don't mean to be so grouchy.' She grinned ruefully. 'It's just that I'd planned what my evening meal would be : scallops and raw tuna marinaded in lemon juice and herbs, followed by spring lamb. Then I rather fancied the apple strudel and cream.'

'I'll buy sandwiches for the journey,' I said. 'Cheese and salad on brown, with an apple to follow.'

'Whoopee.'

It was still not quite eight o'clock when we left the hotel with our bags and boots. I insisted on paying for the unused second night, and apologised to the perplexed owner.

'They probably think it's a lover's tiff,' said Kim.

'They probably think we're fair-weather walkers from London, fleeing from this rain.'

It was still raining as we drove off in the growing darkness, a horrible June evening. The windscreen wipers slapped down water, and Kim put on some music. Bent jazzy notes of a saxophone filled the car, drowned out the patter of wild weather. We sat in a silence that was not uncomfortable. Gradually the rain ceased, although puddles in the road still sprayed up under our tyres, and Kim had to turn on the wipers every time a lorry thundered by in the opposite direction.

I sat back wearily, and gazed at the countryside flowing past. I could see my face, a hazy blur, in the window. I hadn't been able to stay, but I didn't really know what I was going back for. What should I do now? My life was at an impa.s.se. Maybe the only thing to do was to return to Alex's couch and try to sort out all the ugly, itchy inconsistencies. With Alex, I had managed to illuminate one sickening patch of my past, but everything else lay in shadow. Perhaps I had to illuminate all of that, too. I felt unutterably tired at the very thought, as if my bones ached. When I had begun this journey back into my childhood, I had used the image of a black hole in the visible landscape of my past. Now it seemed as if, like the negative of a photograph, that image had been reversed. The only thing that was visible, dazzlingly visible, was that which had been obscure. Topsy-turvy land ruled over by a dead child.

'Can you turn the light on while I try to find another tape?' asked Kim, scrabbling among the mess of ca.s.sette cases in the compartment of her door.

'Sure.' I blinked in the light, and the world outside the car was blotted out. 'You know, Kim, it all feels so inside out. When I walked up Cree's Top this morning, I felt exactly like Alice in the looking-gla.s.s garden, where everything is back to front, and in order to get somewhere you have to walk away from it. Strange, isn't it?'

I blinked back unexpected tears, and gazed at the window. A middle-aged woman, her thin face lined with worry, stared back, stuck in her world on the other side of the gla.s.s. We looked at each other, eyes wide and appalled. She wasn't a stranger; we knew each other quite well though perhaps not well enough. A cold knife was slicing through my brain. Oh no, oh dear G.o.d, please no. What had I done?

I reached up and turned off the light. A flute, haunting, silver, trembled in the air. The woman's face was extinguished. I had been looking at myself. Of course. I was that girl on the hillside, Natalie for an hour; I had seen myself on that hillside, and tracked myself down. I had been in the looking-gla.s.s garden and I had followed my own image and when I had found myself I had lost myself most terribly. Most terribly. I felt a scream rising up in me and clapped my hand over my mouth. It had never been Natalie on the hill; it had only ever been me, Natalie's friend, her lookalike. It was me who had been seen all those years ago by an old man on his way to dismantle the marquee, me who had been called Natalie. It was me for whom I had searched among my living nightmares.

'Please Kim. Please can you drop me off at the next tube station.'

We were coming into the suburbs of London and I knew where I had to go next.

Kim looked at me in astonishment but obediently braked.

'I hope you know what you're doing, Jane, because I certainly don't.'

I kissed her on the cheek then gave her a long hug.

'I know what I'm doing; for the first time in a long long while I know what I'm doing. There's something I've got to sort out and I think it's going to be painful.'

'Jane,' said Kim, as I turned to go. 'If you ever get through this you owe me one. More than one.'

Thirty-Nine.

'h.e.l.lo?'

'h.e.l.lo, is that Dr Thelma Scott?'

'Yes.'

'This is Jane Martello, you may remember we met at...'

She interrupted me with a new note of interest in her voice.

'Yes, I remember.'

'I know this will sound stupid but could I come and see you?'

'What? Now?'

'Yes, if that's all right?'

'It's Sat.u.r.day night, how do you know I'm not having a dinner party or going to a nightclub?'

'I'm sorry, I don't want to interrupt anything.'

'That's all right, I'm reading a novel. Are you sure this is important? You can't just ask me over the phone?'

'If it isn't, you can send me away. Just give me five minutes.'

'All right, where are you?'

'Hanger Lane tube station. Should I get a taxi?'

'No, you're quite close. Just take the tube to Shepherd's Bush.'

She gave me some brief instructions and in a few minutes I was walking out of Shepherd's Bush tube station and around the corner into a quiet residential street by Wood Lane. Knocking at the door, I was greeted by the small woman with the alert expression I remembered from before, but dressed casually in jeans and a very bright sweater. She had a slightly sardonic smile, as if I were acting up to expectations, but her handshake was friendly enough.

'Are you hungry?'

'No, I'm not.'

'Then I'm afraid you'll have to watch me eat. Come through to the kitchen. No smoking, I'm afraid,' she said, noticing the cigarette in my hand. I tossed it back onto the path. In the kitchen she poured herself a gla.s.s of chianti and I asked for nothing but tap water.

'Since you're not eating, I'll just nibble a bit,' she said. 'Now what was it you wanted to see me about.'

And as we talked she prepared and ate the most enormous selection of food: pistachios, olives stuffed with anchovies and chillies, tortilla chips dipped in a guacamole from the fridge, focaccia with mozzarella and Parma ham with a large splash of olive oil.

'Are you a psychoa.n.a.lyst?'

'No, I'm a psychiatrist. Does it matter?'

'You know what happened to me, what I've done, don't you?'

'I think so. But you tell me.'

G.o.d, I wanted a cigarette. To help me think. For something to do with my hands. I had to concentrate.

'I've been in therapy with Alex Dermot-Brown since November. I'd had some emotional problems after the body of my dear friend, Natalie, was found. She'd gone missing in the summer of 1969. Alex was particularly interested when I told him that I had been close by when she was last seen alive. We worked over and over that scene, visualising it, and I gradually recovered the memory of seeing her being murdered by her father, my father-in-law, Alan Martello. I confronted him with it and he confessed. He's now... well, you've read the papers.'

'Yes, I have.'

'I've got to ask you something, Dr Scott. Two things, really. Is it possible that someone would confess to a crime they hadn't committed? I mean, why would they?'

'Hang on a second,' Dr Scott said. 'This takes concentration.' She was slicing her focaccia construction into sections. 'There we are. Now, why would you want to ask me that?'

'What I really want to ask is, is it possible to remember something that then turns out to be false? I mean a clear, detailed visual memory.' She started to reply but I carried on speaking. 'I felt I was doing something like retrieving a file on my computer that had been accidentally lost. Once I'd got it back I would never doubt that it was the actual file that I'd typed, would I?'

Dr Scott was now seated at the kitchen table with plates of food radiating out from her. When it became clear that an answer was required, her mouth was full of sandwich and she had to chew energetically and then swallow.

'Call me Thelma, by the way. My name's an interesting example of the problems of transmission. It comes from a Marie Corelli novel written in the 1880s. It's the name of the heroine, who is Norwegian. I once went to a conference in Bergen and began my speech by saying that it was appropriate I was there because I had a Norwegian name et cetera et cetera. Afterwards, a man came up to me and told me that actually Thelma wasn't a Norwegian name at all. Corelli must have misheard, or something. Or made it up.'

'So your name is a mistake?'

'Yes, all of us Thelmas ought to be recalled and given authentic names.' She laughed. 'It doesn't matter, as long as one doesn't take ideas about cultural tradition too seriously.

'Your comparison with the computer is interesting. Even neurologists have no precise model for the way that memory works, so we all invent our own rough-and-ready metaphors. Sometimes the memory can be like a filing system. A whole section of it might get lost, perhaps the bit dealing with a cla.s.s you were in at school. Then, by chance, you meet somebody who was in that cla.s.s, he provides a few clues and you suddenly recapture a whole lot of memories you didn't know you had.

'The problem is when metaphors take over and start to a.s.sume a false reality. The filing system comparison might lead you to believe that everything you have ever experienced can potentially be recaptured and re-experienced, provided you can find the right stimulus. I would compare some memories to a sandcastle on a beach. Once the sea has come in and washed it away, it is gone, and it can't be precisely recreated, even in theory. Is that all you wanted to talk to me about?'

'Of course not. I'm desperate and I don't know whom to talk to.'

'Why don't you talk to Alex Dermot-Brown?'

'I don't think Alex would be very receptive to what I'm about to say.'

'And you think I'm hostile enough to Alex to believe it,' said Thelma, pouring herself a third (or was it a fourth?) large gla.s.s of wine.

'Look, at the conference where we met, I also met some good, damaged women who said that they would support me and believe me and not question me. I'm standing on the edge of something terrible but what's important is that I don't want to be supported. I don't want to be believed if I'm wrong. Do you see what I'm saying?'

'Not quite, but go on.'

'Let me give you the important details. The last witness who saw Natalie alive saw her by a river near her home on Sunday 27 July 1969. The work on my memory with Alex was based on the fact that I was there, right by where it had happened at the very same time. I was having a pa.s.sionate love affair with Natalie's brother at the time and I went down to the River Col, and sat there with my back against the small hill that separated me from Natalie. In an impulsive adolescent gesture I took some poems I had written, screwed them up, threw them into the river and watched them drift away round the bend of the river.'

Thelma raised an eyebrow. 'Is all this relevant?'

'Yes, very. This was the original account I gave Alex, the bit I remembered without any question, the bit there's no doubt about.'

'So?'

'I walked down to the river this morning, for the first time since it happened. When I got to the spot I'd remembered, the river was flowing the wrong way.'

'How do you mean "the wrong way"?'

'It sounds stupid but it's true. I threw a piece of paper and it didn't float away from me, but towards me.'

Thelma looked disappointed. She shrugged. Was this all?

'It was quite simple,' I continued. 'I turned and walked over the small rise to the other side, and I realised that this was where I had sat and thrown the paper in. In fact, I threw another piece in and it floated away and around the bend, just as I had remembered.'

Thelma's expression had chilled now. She looked distant, a little embarra.s.sed. She wasn't even eating with the same energy. I could see that she was starting to wonder how she could get rid of me without too much fuss.

'I'm sorry,' she said, 'I'm sure I'm being dense but I can't quite see where we're heading. I don't see why it matters that you got things the wrong way round.'

'It wasn't just the wrong way round. The bridge from where the witness saw Natalie was on that side of the hill as well. But bear with me for just one more minute. For reasons I won't go into, I've just received a whole lot of stuff from when I used to spend summers at Natalie's house. It included the diary I kept during that summer. It finished two days before Natalie was last seen, so I didn't pay it much attention. But then when I looked at it today, an interesting detail occurred to me. It always seemed strange that Natalie's body was never found. When she was discovered in October, it seemed to me, at least even stranger. It was a brilliant place to bury a body because it was right under our noses, in the garden just a few yards from the house. But how could it be done?'

'I don't know. Tell me,' said Thelma with obvious impatience.

'My diary reminded me that a barbecue was being built in front of the house and it was completed on the very morning of a party that was held on Sat.u.r.day the twenty-sixth of July, the day before Natalie was last seen. This morning I looked at the hole where Natalie's body was found, and I saw the remains of that barbecue. The barbecue was made of brick installed in clay tiles set in concrete mortar. There are only bits of it now because the barbecue was removed and the clay tiles broken up when Martha that's my mother-in-law extended the lawn. But the point is that the murderer buried Natalie's body in the hole knowing that it was about to be covered with concrete, tiles and a heavy brick construction.'

'Wouldn't a hole in the ground be the first place where the police would look?'

'But it wasn't a hole in the ground, don't you see? When Natalie was last seen on the twenty-seventh, the barbecue had already been in situ in situ for more than twenty-four hours. It would obviously be impossible to place a corpse under a brick barbecue that had already been constructed.' for more than twenty-four hours. It would obviously be impossible to place a corpse under a brick barbecue that had already been constructed.'

'Well, yes, so aren't you answering your own question?'

'You're not following me. Natalie couldn't have died on the twenty-seventh, let alone the twenty-eighth, when she was reported missing. She was already dead and buried by the morning of the party on the twenty-sixth.'

Thelma looked puzzled, but she was alert now.

'But you said that she was actually seen on the twenty-seventh?'

'Yes. But what if I told you that Natalie and I were the same age, we had the same complexions, dressed in the same clothes. And also that she was well known in the neighbourhood and I was only there in the summer, so that there were plenty of local people who had never met me? And if I now seem to have discovered that I was in the same place at the same time where Natalie was last seen alive. What then?'