'I thought she was mad. Well, what else would I think? Michel thought the same when he arrived. More or less threw her out. Told me to forget about her. She was a crazy woman trying to get to him through me. Typical of him to decide it was all about him. We rowed. I went for a walk to clear my head. I didn't believe Sally. But I didn't exactly disbelieve her either, even then. What she'd said made a horrible kind of sense. It slotted into those holes in my life. It wasn't something I could just ignore, however much I wanted to.

'Sally hadn't gone far, of course. She was waiting for me at the corner of the street, as I suppose I'd half-hoped she would be. Mad or sane? I didn't know. But I wanted to hear more.

'It was still light. I walked with her to Southfields Tube station. I listened as she talked. I even… let her hold my hand. I made a deal with her. I'd think about what she'd said. I'd ask my… "parents"… some questions and see what answers I got. I'd meet her on Friday morning, while Michel was with his coach, to talk some more. We agreed the boating lake in Wimbledon Park as a rendezvous. She kissed me and went into the station. There were lots of people about, trickling home from the tennis. I lost sight of her in the crowd. And I never saw her again.

'I never got the chance to put any questions to Roy and Jean either. Michel had called them while I was out and they were at the flat when I got back. They were the ones asking the questions. Why had I let her in? Why had I talked to her? Why had I encouraged her? I was gobsmacked. It was like I'd done something wrong – really wrong. And I had, of course. Just when it ought to have been impossible, too late, way past any danger – I'd learned the truth.

'I didn't know that then, of course. I only knew their reaction was all wrong. It was so out of proportion if Sally was just a nutter. They were taking me back to Monte Carlo right away, they said. Michel sided with them, said he couldn't concentrate on his tennis with so much going on. I saw through him that night as well. I didn't bother to argue. I could tell it was a waste of breath. I said OK, fine, we'll go. They were happy with that. They believed I meant it. They believed most things I said, actually. Just like I believed most things they said. Until then.

'Roy and Jean went back to their hotel, saying they'd collect me in the morning. I decided there and then I wasn't going to be collected. I started another row with Michel, knowing he'd react by storming out and driving round London in his sponsored Ferrari. He was a pretty predictable kind of guy. Once he was out of the way, I packed as much as I could into a rucksack – and left.

'I walked all the way into the centre of London. It was a warm night. I remember sitting on the Embankment at dawn thinking you've done it now, girl, you really have. I wasn't short of money, of course. I wasn't homeless, like other people my age I saw on the streets. I bought breakfast, tried to stop feeling sorry for myself and asked a policeman where I could look up back copies of national newspapers. He said he'd never been asked that one before. But he knew the answer.

'So, I ended up spending most of the day in the Newspaper Library at Colindale. As soon as I saw one of the photographs of Tamsin Hall, I knew. Sally had told me the truth. I read every report there was to read on the case. I stayed there till closing time. I went in as Cherie Hedgecoe. I came out… as someone else.

'I spent that night at a hotel opposite Euston station. Early next morning, I went back to Wimbledon. It was risky, of course. I knew that. But I had to see Sally again. I had to tell her I believed her and ask her… what the fuck I was supposed to do next. I waited for her in the park for hours. Hours and hours. She never turned up, obviously. She was already dead by then. I didn't find that out till I read it in the paper next morning, though. I was checking through it to see if I'd been reported missing. It looked like I hadn't. Then I saw Sally's photograph and the words in the headline: FOUND DEAD.

'They'd killed her. I was certain of that. Not Roy and Jean. But whoever they'd told about her. Whoever was behind the whole crazy fucking thing. They'd ordered her death like they'd ordered Tamsin's abduction – my abduction. Eddie Waldron might have carried out the order. If not him, then someone like him. But who actually did it doesn't matter. What matters is who gave the order. And why.

'I still don't know the answer. And back then I didn't even want to find out. I was so frightened. So alone and so frightened. There was no-one I could trust. Sally had said my real parents had been suspiciously eager to believe Radd's confession and that's how it looked to me too. Like they might be in on it as well, whatever it was. I couldn't fit all the possibilities inside my head. I was just… running scared.

'So that's what I did… I ran. For a long time. For years. India. Hawaii. South America. All over. I went wherever I wouldn't be known. A guy I met in Nepal fixed me up with a fake French passport and I became Chantelle Fontanet. I'll always be Chantelle now, Shadow Man. Never Cherie. Never even Tamsin. Chantelle is them added together. Them transcended.

'But not forgotten. You can only run for so long. Sooner or later, pretending you don't care what the truth is about your life doesn't cut it any more. Last summer, or winter where I was, in Brazil, I came face to face with the realization that I couldn't leave the mystery alone any longer. That I had to try… to find the real me… and the answers to all those questions.

'Sally had told me Oliver and Jane were divorced. She'd also told me Jeremy was living with his father here in Jersey. Whatever was behind my abduction, however much my real parents knew, I felt sure Jeremy had to be innocent. He was only ten years old at the time, after all. I reckoned he was the one member of the family I might be able to trust. Might. I had to check him out first. I came to Jersey and tracked him down to St Aubin. I watched him going out with his sailing classes. I spied on him at the flat. I hung around, trying to work up the courage to approach him.

'As it turned out, I didn't have to. He approached me. He'd noticed the attention I was paying him and one day he surprised me on the steps up to Market Hill. Demanded to know what I was up to. I ummed and ahhed a bit. And then… then he said he recognized me. What would you call it? Sibling instinct? I don't know. But it was true. I saw it in his eyes. Just as he saw something in mine. "It's you, isn't it?" he said. "You've come back." And I had.

'Jem was on pretty poor terms with Oliver by then. He didn't quite trust him any more. Or Marilyn. Things had never been the same since Radd's confession, he said. There was no good reason to believe Radd was telling the truth. But they did. That left Jem out in the cold. The way he saw it, my turning up was his reward for keeping the faith. He was… exultant. High on the joy of it. So was I. Those first few months, last summer and autumn… were the best. Just the absolute best.

'We rented a flat in St Malo. It seemed safer to spend most of our time together in France. Once the sailing season was over, Jem was hardly ever here. I had him all to myself. We were careful. I dyed my hair. And we never used mobiles. Too easy to trace, Jem said. He came up with the idea of coloured contact lenses as well. And he taught me to stop doing that thing with my lower lip that had caught Sally's eye in Hello! People must have taken us for boyfriend and girlfriend. I suppose that's how it felt to us too, in a way. It was a kind of romance. A voyage of rediscovery, Jem called it.

'But there were still those questions, niggling away at us, itching to be asked… and answered. It seemed worse for Jem than for me. Our parents were two people I'd never known. But he'd loved and trusted them implicitly. He needed to know the truth more than I did. He couldn't let it go.