I want to talk about the Norfolk trip, and all the things that happened that day, but I'll first have to go back a bit, to give you the background and explain why it was we went.

Our first winter was just about over by then and we were all feeling much more settled. For all our little hiccups, Ruth and I had kept up our habit of rounding off the day in my room, talking over our hot drinks, and it was during one of those sessions, when we were larking around about something, that she suddenly said: "I suppose you've heard what Chrissie and Rodney have been saying."

When I said I hadn't, she did a laugh and continued: "They're probably just having me on. Their idea of a joke. Forget I mentioned it."

But I could see she wanted me to drag it out of her, so I kept pressing until in the end she said in a lowered voice: "You remember last week, when Chrissie and Rodney were away? They'd been up to this town called Cromer, up on the north Norfolk coast."

"What were they doing there?"

"Oh, I think they've got a friend there, someone who used to live here. That's not the point. The point is, they claim they saw this... person. Working there in this open-plan office. And, well, you know. They reckon this person's a possible. For me."

Though most of us had first come across the idea of "possibles" back at Hailsham, we'd sensed we weren't supposed to discuss it, and so we hadn't--though for sure, it had both intrigued and disturbed us. And even at the Cottages, it wasn't a topic you could bring up casually. There was definitely more awkwardness around any talk of possibles than there was around, say, sex. At the same time, you could tell people were fascinated--obsessed, in some cases--and so it kept coming up, usually in solemn arguments, a world away from our ones about, say, James Joyce.

The basic idea behind the possibles theory was simple, and didn't provoke much dispute. It went something like this. Since each of us was copied at some point from a normal person, there must be, for each of us, somewhere out there, a model getting on with his or her life. This meant, at least in theory, you'd be able to find the person you were modelled from. That's why, when you were out there yourself--in the towns, shopping centres, transport cafés--you kept an eye out for "possibles"--the people who might have been the models for you and your friends.

Beyond these basics, though, there wasn't much consensus. For a start, no one could agree what we were looking for when we looked for possibles. Some students thought you should be looking for a person twenty to thirty years older than yourself--the sort of age a normal parent would be. But others claimed this was sentimental. Why would there be a "natural" generation between us and our models? They could have used babies, old people, what difference would it have made? Others argued back that they'd use for models people at the peak of their health, and that's why they were likely to be "normal parent" age. But around here, we'd all sense we were near territory we didn't want to enter, and the arguments would fizzle out.

Then there were those questions about why we wanted to track down our models at all. One big idea behind finding your model was that when you did, you'd glimpse your future. Now I don't mean anyone really thought that if your model turned out to be, say, a guy working at a railway station, that's what you'd end up doing too. We all realised it wasn't that simple. Nevertheless, we all of us, to varying degrees, believed that when you saw the person you were copied from, you'd get some insight into who you were deep down, and maybe too, you'd see something of what your life held in store.

There were some who thought it stupid to be concerned about possibles at all. Our models were an irrelevance, a technical necessity for bringing us into the world, nothing more than that. It was up to each of us to make of our lives what we could. This was the camp Ruth always claimed to side with, and I probably did too. All the same, whenever we heard reports of a possible--whoever it was for--we couldn't help getting curious.

The way I remember it, sightings of possibles tended to come in batches. Weeks could go by with no one mentioning the subject, then one reported sighting would trigger off a whole spate of others. Most of them were obviously not worth pursuing: someone seen in a car going by, stuff like that. But every now and then, a sighting seemed to have substance to it--like the one Ruth told me about that night.

ACCORDING TO RUTH, Chrissie and Rodney had been busy exploring this seaside town they'd gone to and had split up for a while. When they'd met up again, Rodney was all excited and had told Chrissie how he'd been wandering the side-streets off the High Street, and had gone past an office with a large glass front. Inside had been a lot of people, some of them at their desks, some walking about and chatting. And that's where he'd spotted Ruth's possible.

"Chrissie came and told me as soon as they got back. She made Rodney describe everything, and he did his best, but it was impossible to tell anything. Now they keep talking about driving me up there, but I don't know. I don't know if I ought to do anything about it."

I can't remember exactly what I said to her that night, but I was at that point pretty sceptical. In fact, to be honest, my guess was that Chrissie and Rodney had made the whole thing up. I don't really want to suggest Chrissie and Rodney were bad people--that would be unfair. In many ways, I actually liked them. But the fact was, the way they regarded us newcomers, and Ruth in particular, was far from straightforward.

Chrissie was a tall girl who was quite beautiful when she stood up to her full height, but she didn't seem to realise this and spent her time crouching to be the same as the rest of us. That's why she often looked more like the Wicked Witch than a movie star--an impression reinforced by her irritating way of jabbing you with a finger the second before she said something to you. She always wore long skirts rather than jeans, and little glasses pressed too far into her face. She'd been one of the veterans who'd really welcomed us when we'd first arrived in the summer, and I'd at first been really taken by her and looked to her for guidance. But as the weeks had passed, I'd begun to have reservations. There was something odd about the way she was always mentioning the fact that we'd come from Hailsham, like that could explain almost anything to do with us. And she was always asking us questions about Hailsham--about little details, much like my donors do now--and although she tried to make out these were very casual, I could see there was a whole other dimension to her interest. Another thing that got to me was the way she always seemed to want to separate us: taking one of us aside when a few of us were doing something together, or else inviting two of us to join in something while leaving another two stranded--that sort of thing.

You'd hardly ever see Chrissie without her boyfriend, Rodney. He went around with his hair tied back in a ponytail, like a rock musician from the seventies, and talked a lot about things like reincarnation. I actually got to quite like him, but he was pretty much under Chrissie's influence. In any discussion, you knew he'd back up Chrissie's angle, and if Chrissie ever said anything mildly amusing, he'd be chortling and shaking his head like he couldn't believe how funny it was.

Okay, I'm maybe being a bit hard on these two. When I was remembering them with Tommy not so long ago, he thought they were pretty decent people. But I'm tell............