She shrugged, one-shouldered. "I'm not very good with paradox."

"I think I am, actually," I said thoughtfully.

Cassie rolled over onto her back and laughed. "You should put that in a personal ad. Male, six foot, good with paradox-"

"-abnormally studly-"

"-seeks his very own Britney for-"

"Ewww!"

She cocked an eyebrow at me, innocently. "No?"

"Give me some credit. Britney is exclusively for those with cheap tastes. It would have to be Scarlett Johansson at least."

We laughed, subsided. I sighed comfortably and arranged myself around the sofa's familiar quirks; Cassie reached out one arm to turn off the lamp. "Night. Sleep tight."

"Sweet dreams."

Cassie sleeps as lightly and easily as a kitten; after a few seconds I heard her breathing slow and deepen, the tiny catch at the top of each breath that told me she had drifted off. I am the opposite: once I'm asleep it takes an extra-loud alarm clock or a kick in the shins to wake me, but it can be hours of tossing and fidgeting before I get there. But somehow I always found it easier to sleep at Cassie's, in spite of the lumpy, too-short sofa and the grouchy creaks and ticks of an old house settling for the night. Even now, when I'm having trouble falling asleep, I try to imagine myself back on that sofa: the soft, worn flannel of the duvet cover against my cheek, a spicy tang of hot whiskey still warming the air, the tiny rustles of Cassie dreaming across the room.

A couple of people clattered into the house, shushing each other and giggling, and went into the flat downstairs; peaks of conversation and laughter filtered up, faint and muffled, through the floor. I matched the rhythm of my breathing to Cassie's and felt my mind sliding pleasurably down into dreamy, nonsensical tangents-Sam was explaining how to build a boat, and Cassie was sitting on a window ledge between two stone gargoyles and laughing. The sea is several streets away and there was no way I could have heard it, but I imagined I did all the same.

9

In my memory, we spent a million nights in Cassie's flat, the three of us. The investigation only lasted a month or so, and I'm sure there must have been days when one or another of us was off doing something else; but over time those evenings have colored the whole season for me, like a brilliant dye flowering slowly through water. The weather dipped in and out of an early, bitter autumn; wind whined through the eaves, and raindrops seeped in the warped sash windows and trickled down the panes. Cassie would light a fire and we would all spread out our notes on the floor and bat theories back and forth, then take turns getting dinner-mainly pasta variations from Cassie, steak sandwiches from me, surprisingly exotic experiments from Sam: lavish tacos, some Thai thing with spicy peanut sauce. We would have wine with dinner, move on to whiskey in various forms afterwards; when we started to get tipsy, we would pack the case file away and kick off our shoes and put on music and talk.

Cassie, like me, is an only child, and we were both enthralled by Sam's stories about his childhood-four brothers and three sisters piled into an old white farmhouse in Galway, playing mile-wide games of Cowboys and Indians and sneaking out at night to explore the haunted mill, with a big quiet father and a mother dealing out oven-warm bread and raps with a wooden spoon and counting heads at mealtimes to make sure nobody had fallen into the stream. Cassie's parents died in a car crash when she was five, and she was brought up by a gentle, older aunt and uncle, in a ramshackle house in Wicklow, miles from anything. She talks about reading unsuitable books from their library-The Golden Bough, Ovid's Metamorphoses; Madame Bovary, which she hated but finished anyway-curled up in a window seat on the landing, eating apples from the garden, with soft rain going past the panes. Once, she says, she wriggled under an ancient and hideous wardrobe and found a china saucer, a George VI penny and two letters from a World War I soldier whose name nobody recognized, with bits blacked out by censors. I don't remember much from before I was twelve, and after that my memories are mainly arranged in rows-rows of gray-white dormitory beds, rows of echoing, bleach-smelling cold showers, rows of boys in archaic uniforms droning Protestant hymns about duty and constancy. To both of us, Sam's childhood was something out of a storybook; we pictured it in pencil drawings, apple-cheeked children with a laughing sheepdog jumping around them. "Tell us about when you were little," Cassie would say, snuggling into the futon and pulling her sleeves down over her hands to hold her hot whiskey.

In many ways, though, Sam was the odd man out in these conversations, and a part of me was pleased at this. Cassie and I had spent two years building our routine, our rhythm, our subtle private codes and indicators; Sam was, after all, there by our favor, and it seemed only fair that he should play a supporting role, present but not too present. It never seemed to bother him. He would stretch out on the sofa, tilting his whiskey glass to make the firelight throw spots of amber on his sweater, and watch and smile as Cassie and I argued over the nature of Time, or T. S. Eliot, or scientific explanations for ghosts. Adolescent conversations, no doubt, and made more so by the fact that Cassie and I brought out the brat in each other ("Bite me, Ryan," she would say, narrowing her eyes at me across the futon, and I would grab her arm and bite her wrist till she yelled for mercy), but I had never had them in my adolescence and I loved them, I loved every moment.

I am, of course, romanticizing; a chronic tendency of mine. Don't let me deceive you: the evenings may have been roast chestnuts around a cozy turf fire, but the days were a grim, tense, frustrating slog. Officially we were on the nine-to-five shift, but we were in before eight every morning, seldom left before eight at night, took work home with us-questionnaires to correlate, statements to read, reports to write. Those dinners started at nine o'clock, ten; it was midnight before we stopped talking shop, two in the morning by the time we had unwound enough to go to bed. We developed an intense, unhealthy relationship with caffeine and forgot what it was like not to be exhausted. On the first Friday evening, a very new floater called Corry said, "See you Monday, lads," and got a round of sardonic laughter and slaps on the back, as well as a humorless "No, Whatsyourname, I'll see you at eight tomorrow morning and don't be late" from O'Kelly.

Rosalind Devlin hadn't come in to see me that first Friday, after all.

Around five o'clock, edgy from waiting and unaccountably worried that something might have happened to her, I rang her mobile. She didn't answer. She was with her family, I told myself, she was helping with the funeral arrangements or looking after Jessica or crying in her room; but that unease stayed with me, tiny and sharp as a pebble in my shoe.

On the Sunday we went to Katy's funeral, Cassie and Sam and I. The thing about murderers being irresistibly drawn to the graveside is mostly legend, but still, the off-chance was worth it, and anyway O'Kelly had told us to go on the grounds that it was good PR. The church had been built in the 1970s, when concrete was an artistic statement and when Knocknaree was supposed to become a major metropolis any day now; it was huge and chill and ugly, gauche semi-abstract Stations of the Cross, echoes creeping dismally up to the angled concrete ceiling. We stood at the back, in our best unobtrusive dark clothes, and watched as the church filled up: farmers holding flat caps, old women in headscarves, trendy teenagers trying to look blasé. The little white coffin, gold-trimmed and terrible, in front of the altar. Rosalind stumbling up the aisle, shoulders heaving, supported by Margaret on one side and Auntie Vera on the other; behind them Jonathan, glassy-eyed, guided Jessica towards the front pew.