“Whoa,” Abby said suddenly, sitting back on her heels. “Check this out.”

She was holding up a dress: robin’s-egg blue with white polka dots and a white collar and sash, little cap sleeves and a full skirt made to fly up when you twirled, pure lindy hop. “Wow,” I said, disentangling myself from my puddle of fabric and going over to check it out. “Think it was Uncle Simon’s?”

“I don’t think he had the figure for it, but we’ll check the photo album.” Abby held the dress at arm’s length and examined it. “Want to try it on? I don’t think it has moths.”

“Go for it. You found it.”

“It’d never fit me. Look-” Abby got to her feet and held the dress against herself. “It’s for someone taller. The waist would be down around my arse.”

Abby was maybe five foot two, but I kept forgetting; it was hard to think of her as small. “And it’s for someone skinnier than me,” I said, trying the waist against mine, “or wearing a serious corset. I’d burst it.”

“Maybe not. You lost weight when you were sick.” Abby threw the dress over my shoulder. “Try it.”

She gave me a quizzical look when I headed for my bedroom to change: it was obviously out of character, but I couldn’t do much about that, except hope she would put it down to self-consciousness about the bandage or something. The dress actually did fit, more or less-it was tight enough that the bandage left a bulge, but there was nothing dodgy about that. I did a quick check to make sure the wire didn’t show. In the mirror I looked breathless and mischievous and daring, ready for anything.

“Told you,” Abby said, when I came out. She spun me round, retied the sash in a bigger bow. “Let’s go wow the boys.”

We ran downstairs calling, “Look what we found!” and by the time we got down to the sitting room the sander was off and the guys were waiting for us. “Oh, look at you!” Justin cried. “Our little jazz baby!”

“Perfect,” Daniel said, smiling at me. “It’s perfect.”

Rafe swung one leg over the piano stool and swept a finger up the keys in a great, expert flourish. Then he started to play, something lazy and tempting with a sideways swing to it. Abby laughed. She gave the bow of my sash another tug, tightening it; then she went to the piano and started to sing.

“Of all the boys I’ve known and I’ve known some, until I first met you I was lonesome…”

I had heard Abby sing before, but only to herself when she thought no one was listening, never like this. That voice: it was the kind you don’t hear these days, a magnificent, full-blown contralto straight out of old war films, a voice for smoky nightclubs and marcel-waved hair, red lipstick and a blue saxophone. Justin put the sander down, clicked his heels together neatly and bowed. “May I have the honor of this dance?” he asked, and held out his hand to me.

For a second I wasn’t sure. What if Lexie had had two left feet, what if she hadn’t had two left feet and my new clumsiness gave me away, what if he held me too close and felt the battery pack hard under the bandage… But I always loved dancing and it seemed like forever since I had danced or wanted to, so long ago I couldn’t remember the last time. Abby winked at me without missing a note and Rafe threw in an extra little riff, and I caught Justin’s hand and let him pull me out of the doorway.

He knew what he was doing: smooth steps and his hand steady in mine as he spun me in slow circles around the room, floorboards soft and warm and dusty under my feet. And I hadn’t lost the knack, after all, I wasn’t stepping on Justin’s feet or tripping over my own; my body swayed with his sure and agile as if I had never walked into a chair in my life, I couldn’t have put a foot wrong if I had tried. Ribs of sunlight flashing across my eyes, Daniel leaning against the wall and smiling with a crumple of sandpaper forgotten in his hand, my skirt whirling up like a bell as Justin swung me away from him and then in again. “And so I rack my brain trying to explain all the things that you do to me…” Smell of polish, and the sawdust spinning lazy curls through the long columns of light. Abby with one palm lifting and her head thrown back, throat exposed and the song tossed up through the empty rooms and battered ceilings to the whole blazing sunset sky.

For a second it came back to me, when I had last danced like this: me and Rob, on the roof of the extension below my flat, the night before everything went horribly wrong. Somehow it didn’t even hurt. It was so far away; I was buttoned tight and untouchable in my blue dress and that was a sweet sad thing that had happened to some other girl, a long time ago. Rafe was picking up the rhythm and Abby was swaying faster, snapping her fingers: “I could say bella, bella, even say wunderbar, each language only helps me tell you how grand you are…” Justin caught me by the waist and spun me off the floor in a great flying circle, his face flushed and laughing close to mine. The wide bare room tossed Abby’s voice back and forth as if there were someone harmonizing in every corner and our footsteps rang and echoed till it sounded like the room was full of dancers, the house calling up all the people who had danced here across centuries of spring evenings, gallant girls seeing gallant boys off to war, old men and women straight-backed while outside their world disintegrated and the new one battered at their doors, all of them bruised and all of them laughing, welcoming us into their long lineage.

"Well well well,” Frank said, that night. "You know what today is, right?”

I had no idea. Half my mind was still back at Whitethorn House. After dinner Rafe had dug out a tattered, yellowish songbook from inside the piano stool and kept going with the inter-war theme, Abby was singing along from the spare room-“Oh, Johnny, how you can love”-while she went back to rummaging and Daniel and Justin did the washing up, and the rhythm of it had bounced in my heels, sweet and saucy and tempting, all the way down the lawn and out the back gate. For a second I had actually considered just staying home, leaving Frank and Sam and the mystery pair of eyes to their own devices for one evening. It wasn’t like I was getting anything useful done out here. The night had turned cloudy, needle-fine drizzle was spattering onto the communal jacket, and I didn’t like having the torch on while I was on the phone; I couldn’t see six inches in front of my face. A whole coven of knife-happy stalkers could have been doing the Macarena around the cottage and I would never have known.

“If it’s your birthday,” I said, “you might have to wait for your present.”

“Very funny. It’s Sunday, babe. And unless I’m much mistaken, you’re still in Whitethorn House, snug as a bug in a rug. Which means we’ve won our first battle: you made it through the week without getting caught. Congratulations, Detective. You’re in.”

“I guess I am,” I said. I had stopped counting the days, somewhere along the way. I decided this was a good sign.

“So,” Frank said. I could hear him arranging himself more comfortably, turning down the outraged talk-radio caller in the background: he was at home, wherever home was since Olivia had kicked him out. “Let’s have a summary of Week One.”

I pulled myself up onto a wall and took a second to get my head clear before I answered. Under all the easy messing around, Frank is pure business: he wants reports like any other boss, and he likes them clear, thorough and succinct.

“Week One,” I said. “I’ve inserted myself into Alexandra Madison’s home and her place of study, apparently with success: no one’s shown any sign of suspicion. I’ve searched as much of Whitethorn House as is feasible, but I haven’t found anything to point us in a specific direction.” This was basically true; the diary presumably pointed somewhere, but so far I had no idea where. “I’ve made myself available as much as possible-to known associates, by attempting to be alone on regular occasions during the day and evening, and to unknown ones by ensuring that I’m visible on these walks. I haven’t been approached by anyone who wasn’t already on our radar, but at this stage that doesn’t rule out an unknown assailant; he could be biding his time. I’ve been approached at various times by all the housemates and a number of students and professors, but all of them seemed concerned primarily with how I was feeling, that kind of thing-Brenda Grealey was a little more interested in the details than you’d expect, but I think that’s just ghoulishness. None of the reactions to Lexie’s stabbing or to her return have raised any red flags. The housemates appear to have concealed the full extent of their distress from the investigating officers, but coming from them, I don’t consider that suspicious behavior. They’re very reserved with outsiders.”