The lane was unpaved and potholey. Trees gone shapeless with years of ivy, hedge branches rattling along the sides of the car and flicking in at my window; and then huge wrought-iron gates, flaking with rust and hanging drunkenly off their hinges. The stone pillars were half drowned in hawthorn grown wild. “Here,” I said.

Frank nodded and turned, and we were looking down an endless, graceful sweep of avenue, between cherry trees crowded with exploded balls of flowers. “Fuck me,” I said. “Why did I have doubts about this, again? Can I sneak Sam in with me in my suitcase, and we can just live here forever?”

“Get it out of your system,” Frank said. “By the time we reach that door, you need to be blasé about all this. Anyway, the house is still shitty, so you can calm down.”

“You told me they’d redone it. I expect cashmere curtains and white roses in my dressing room, or I’m calling my agent.”

“I said they were doing it up. I didn’t say they were magic.”

Then the drive gave a little twist and opened up into a great semicircular carriage sweep, white pebbles speckled through with weeds and daisies, and I saw Whitethorn House for the first time. The photos hadn’t done it justice. You see Georgian houses all over Dublin, mostly turned into offices and undermined by the depressing fluorescents you can see through the windows, but this one was special. Every proportion was balanced so perfectly that the house looked like it had grown there, nested in with its back to the mountains and all Wicklow dropping away rich and gentle in front of it, poised between the pale arc of the carriage sweep and the blurred dark-and-green curves of the hills like a treasure held out in a cupped palm.

I heard Sam take a fast hard breath. “Home sweet home,” said Frank, turning the radio off.

They were waiting for me outside the door, ranged at the top of the steps. In my mind I still see them like that, lacquered gold by the evening sun and glowing vivid as a vision, every fold of their clothes and curve of their faces pristine and achingly clear. Rafe leaning against the railing with his hands in his jeans pockets; Abby in the middle, swayed forwards on her toes, one arm crooked to shade her eyes; Justin, his feet precisely together and his hands clasped behind his back. And behind them, Daniel, framed between the columns of the door, his head up and the light splintering off his glasses.

None of them moved as Frank pulled up and braked, pebbles scattering. They were like figures on a medieval frieze, self-contained, mysterious, spelling out a message in some lost and arcane code. Only Abby’s skirt fluttered, fitfully, in the breeze.

Frank glanced at me over his shoulder. “Ready?”

“Yeah.”

“Good girl,” he said. “Good luck. And we’re go.” He got out of the car and went round to the boot to get my case.

“Mind yourself,” Sam said. He didn’t look at me. “I love you.”

“I’ll be home soon,” I said. There was no way even to touch his arm, under all those unblinking eyes. “I’ll try to ring you tomorrow.”

He nodded. Frank slammed the boot-the sound was wild, enormous, bouncing off the house front and setting crows scattering from the trees-and opened the car door for me.

I got out, putting my hand to my side for a second as I straightened up. “Thanks, Detective,” I said to Frank. “Thanks for everything.”

We shook hands. “My pleasure,” Frank said. “And don’t worry, Miss Madison: we’ll get this guy.”

He pulled out the handle of the case with a neat snap and passed it to me, and I dragged it across the carriage sweep towards the steps and the others.

Still none of them moved. As I got closer I realized, with a shift of focus like a shock. Those straight backs, the lifted heads: there was some tension stretched between the four of them, so tight it hummed high in the silence. The wheels of my case, grating across the pebbles, sounded loud as machine-gun fire.

“Hi,” I said at the bottom of the steps, looking up at them.

For a second I thought they weren’t going to answer, they had made me already, and I wondered wildly what the hell I was supposed to do now. Then Daniel took a step forwards, and the picture wavered and broke. A smile started across Justin’s face, Rafe straightened up and raised one arm in a wave, and Abby came running down the steps and hugged me hard.

“Hey, you,” she said, laughing, “welcome home.” Her hair smelled like camomile. I dropped the case and hugged her back; it was a strange feeling, as if I were touching someone out of an old painting, amazed to find her shoulder blades warm and solid as my own. Daniel nodded gravely at me over her head and ruffled my hair, Rafe grabbed my case and started bumping it up the steps to the door, Justin patted my back over and over and I was laughing too, and I didn’t even hear Frank start the car and drive away.

This is the first thing I thought when I stepped into Whitethorn House: I’ve been here before. It zinged straight through me, straightened my spine like a crash of cymbals. The place bloody well should have looked familiar, all the hours I’d spent staring at photos and video, but it was more than that. It was the smell, old wood and tea leaves and a faint whiff of dried lavender; it was the way the light lay along the scarred floorboards; it was the little taps our footsteps sent flying up the stairwell, echoing softly along the upstairs corridors. It felt-and you’d think I would like this but I didn’t, it flashed danger-sign red right across my mind-it felt like coming home.

From there on, most of that evening is a merry-go-round blur, colors and images and voices whirled together into a burst almost too bright to look at. A ceiling rose and a cracked china vase, a piano stool and a bowl of oranges, running feet on stairs and a rising laugh. Abby’s fingers small and strong on my wrist, leading me out to the flagstoned patio behind the house, curlicued metal chairs, ancient wicker swing seat swaying in the light sweet breeze; great sweep of grass falling away to high stone walls half hidden in trees and ivy, blink of a bird’s shadow across the paving stones. Daniel lighting my cigarette, his hand cupped round the match and his bent head inches from mine. The full ring of their voices hit me like a shock, after the flattened-out video sound, and their eyes were so clear they burned on my skin. Sometimes, still, I wake up with one of their voices strong and close by my ear, fallen straight out of that day: Come here, Justin calls, come outside, the evening’s so lovely; or Abby says, We have to decide what to do with the herb garden, but we were waiting for you, what do you-and I’m awake, and they’re gone.

I must have talked too, somewhere in there, but I can’t remember most of what I said. All I remember is trying to keep my weight forwards on my toes like Lexie did, my voice up in her register, my eyes and my shoulders and my smoke at the right angles, trying not to look around too much and not to move too fast without wincing and not to say anything idiotic and not to whack into the furniture. And God the taste of undercover on my tongue again, the brush of it down the little hairs on my arms. I’d thought I remembered what it was like, every detail, but I’d been wrong: memories are nothing, soft as gauze against the ruthless razor-fineness of that edge, beautiful and lethal, one tiny slip and it’ll slice to the bone.

It took my breath away, that evening. If you’ve ever dreamed that you walked into your best-loved book or film or TV program, then maybe you’ve got some idea how it felt: things coming alive around you, strange and new and utterly familiar at the same time; the catch in your heartbeat as you move through the rooms that had such a vivid untouchable life in your mind, as your feet actually touch the carpet, as you breathe the air; the odd, secret glow of warmth as these people you’ve been watching for so long, from so far away, open their circle and sweep you into it. Abby and I rocked the swing seat lazily; the guys moved in and out through the small-paned French windows between the patio and the kitchen, making dinner-smell of roasting potatoes, sizzle of meat, suddenly I was starving-and calling to us. Rafe came outside to lean on the back of the seat between us and take a drag of Abby’s cigarette. Rose-gold sky deepening and great puffs of cloud streaming like the smoke of some faraway wildfire, cool air rich with grass and earth and growing things. “Dinner!” Justin yelled, against a clatter of plates.