"So what are you thinking?" I asked.

I meant about the case, obviously, but Cassie was in a giddy mood-she generates more energy than most people, and she'd been sitting indoors most of the day. "Will you listen to him? A woman asking a guy what he's thinking is the ultimate crime, she's clingy and needy and he runs a mile, but when it's the other-"

"Behave yourself," I said, pulling her hood over her face.

"Help! I'm being oppressed!" she yelled through it. "Call the Equality Commission." The stroller girl gave us a sour look.

"You're overexcited," I told Cassie. "Calm down or I'll take you home with no ice cream."

She shook back the hood and took off down the strand in a long chain of cartwheels and flips, her coat tumbling around her shoulders. My initial impression of Cassie was satisfyingly spot-on: she did gymnastics for eight years as a kid and was apparently quite good. She quit because competitions and routines bored her; it was the moves themselves she loved, their taut, sprung, risky geometry, and fifteen years later her body still remembers almost all of them. When I caught up with her she was breathless and dusting sand off her hands.

"Better?" I asked.

"Much. You were saying?"

"The case. Work. Dead person."

"Ah. That," she said, instantly serious. She pulled her coat straight and we wandered on down the strand, scuffing at half-buried shells.

"I was wondering," Cassie said, "what Peter Savage and Jamie Rowan were like."

She was watching a ferry, small and neat as a toy, chug determinedly across the horizon line; her face, tipped up to the soft rain, was unreadable. "Why?" I said.

"I'm not sure. Just wondering."

I thought about the question for a long time. My memories of them had rubbed thin with overuse, worn to frail color transparencies flickering on the walls of my mind: Jamie scrambling intent and surefooted up to a high branch, Peter's laugh arcing out of the trompe-l'oeil dazzle of green ahead. Through some slow sea change they had become children out of a haunting storybook, bright myths from a lost civilization; it was hard to believe they had once been real and my friends.

"In what sense?" I said eventually and inanely. "Personality, or looks, or what?"

Cassie shrugged. "Whichever."

"They were both about the same height as me," I said. "Average height, I suppose, whatever that is. They both had a slim build. Jamie had white-blond hair, cut in a bob, and a snub nose. Peter had light brown hair, that floppy cut that little boys have when their mothers cut it for them, and green eyes. I think he would probably have been very handsome."

"And their personalities?" Cassie glanced up at me; the wind flattened her hair sleek as a seal's against her head. Occasionally when we go for walks she links a hand through my arm, but I knew she wouldn't do it now.

In my first year of boarding school I thought about them all the time. I was wildly, devastatingly homesick; I know every child is, in that situation, but I think my wretchedness went well beyond the norm. It was a constant agony, consuming and debilitating as a toothache. At the start of every term I had to be extracted howling and struggling from the car and dragged inside while my parents drove away. You'd think this kind of thing would have made me a perfect target for bullies, but actually they left me severely alone, recognizing, I suppose, that nothing they could do would make me feel any worse. It wasn't that the school was hell on earth or anything, in fact I think it was probably pretty OK as these places go-a smallish school in the countryside, with an elaborate house system and an obsession with sports and various other clichés-but I wanted, more than I have ever wanted anything in my life, to go home.

I coped, in the grand tradition of children everywhere, by retreating into my imagination. I sat on wobbly chairs through droning assemblies and pictured Jamie fidgeting beside me, conjured up every detail of her, the shape of her kneecaps, the tilt of her head. At night I lay awake for hours, boys snoring and muttering all around me, and concentrated with every cell in my body until I knew, beyond any doubt, that when I opened my eyes Peter would be in the next bed. I used to float messages in cream-soda bottles down the stream that ran through the school grounds: "To Peter and Jamie. Please come back please. Love Adam." I knew, you see, that I had been sent away because they had disappeared; and I knew that if they were to run back out of the wood some evening, grubby and nettle-stung and demanding their tea, I would be allowed to come home.

"Jamie was a tomboy," I said. "Very shy of strangers, especially adults, but physically absolutely fearless. You two would have liked each other."

Cassie gave me a sideways half-grin. "In 1984 I was only ten, remember? You guys wouldn't have talked to me."

I had come to think of 1984 as a separate, private world; it came as something of a shock to realize that Cassie had been there, too, only a few miles away. At the moment when Peter and Jamie disappeared she had been playing with her own friends or riding a bike or eating her tea, oblivious to what was happening and to the long, complicated paths that would lead her to me and to Knocknaree. "Of course we would have," I said. "We would have said, 'Give us your lunch money, you little twit.'"

"You do that anyway. Go on about Jamie."

"Her mother was sort of a hippie-long floaty skirts and long hair, and she used to give Jamie yogurt with wheat germ in it for her break at school."

"Ewww," Cassie said. "I didn't even know you could get wheat germ in the eighties. Supposing you wanted to."

"I think she may have been illegitimate-Jamie, not her mother. Her father wasn't in the picture. A few kids used to pick on her about it, till she beat one of them up. I asked my mother where Jamie's dad was, after that, and she told me not to be nosy." I had asked Jamie, too. She had shrugged and said, "Who cares?"

"And Peter?"

"Peter was the leader," I said. "Always, even when we were tiny kids. He could talk to anyone, he was always talking us out of trouble-not that he was a smart arse, I don't think he was, but he was confident and he liked people. And he was kind."

There was a kid on our road, Willy Little. The name would have caused him enough trouble all by itself-I wonder what on earth his parents were thinking-but on top of that he had Coke-bottle glasses, and he had to wear thick hand-knit sweaters with bunnies across the front all year round because there was something wrong with his chest, and he started most of his sentences with "My mother says…" We had cheerfully tortured him all our lives-drawing the obvious pictures on his school copybooks, spitting on his head out of trees, saving up droppings from Jamie's rabbit and telling him they were chocolate raisins, that kind of thing-but the summer we were twelve Peter made us stop. "It's not fair," he said. "He can't help it."

Jamie and I sort of saw his point, although we did argue that Willy could perfectly well have called himself Bill and quit telling people what his mother thought about things. I felt guilty enough to offer him half a Mars bar the next time I saw him, but understandably he gave me a suspicious look and scuttled away. I wondered, absently, what Willy was doing these days. In the movies he would have been a Nobel-prize-winning genius with a supermodel wife; this being real life, he was probably making a living as a medical-research guinea pig and still wearing bunny sweaters.

"That's rare," Cassie said. "Most kids that age are vicious. I'm sure I was."

"I think Peter was an unusual kid," I said.

She stopped to pick up a bright orange cockleshell and examine it. "There's still a chance they could be alive, isn't there?" She dusted sand off the shell against her sleeve, blew on it. "Somewhere."