My heart softened as I checked the lock on the utility room door, did battle with the front-door panel and the lights in the hall, and then climbed the flights of stairs to my own room with a weariness I was having increasing trouble overcoming.

I was passing Bill and Sandra’s room when I thought I heard something. Or perhaps saw it—it was hard to know. A little flicker of movement in the sliver of darkness between the door and the frame. Was it just my imagination? I was so tired. It could be my mind playing tricks on me.

Very, very quietly, not wanting to disturb the girls, I pushed the door with the flat of my hand, listening to it shushing across the thick silver carpet.

Inside, the room was quite empty and still. The curtains were undrawn, and though in London it would have been getting dark, here we were so far north that the sun was only just sliding behind the mountains. Livid squares of reddish light slanted obliquely across the floor, turning the carpet into a kind of fiery chessboard, though the corners of the room were in deep, impenetrable shadow. I let my hand slip over the thick, crisp cotton of their duvet cover as I passed their bed, glancing into the shadows, feeling my pulse quicken with the audacity of this intrusion. If Sandra were watching through the monitor now, what would she see? Someone prowling around her bedroom, fingering her bed linen. I thought I heard a noise . . . I practiced the excuse in my head, but I knew it was no longer true. I had been looking for an excuse.

There was a pair of earrings on the bedside table closest to the door. This must be Sandra’s side. Which meant that Bill slept . . .

I tiptoed around the bed, keeping to the shadows as far as I could. I knew from peering at Maddie and Ellie’s bedroom monitor that the resolution of the images in darkness was not good. It was very hard to make out anything beyond the little pool of warm light cast by the night-light, and in here the contrast between the squares of sunset and the deep shadow in the rest of the room was even greater.

Very, very quietly, I slid open Bill’s bedside table drawer, and looked down at the tumble of personal possessions inside. A watch with a broken strap. A slew of loose change. A few tickets, a hay-fever spray, a comb. I’m not sure what I had been hoping for—but if it was to get a sense of the person who lived here, slept here, laid his head on the crisp white pillow, I was disappointed. It was strikingly impersonal.

I thought of that meeting in the kitchen, of his denimed leg slipping between my thighs with a confident intrusiveness born of long practice, and I felt sick. Who are you?

Suddenly I had to get out, and I hurried across the checkered carpet, no longer caring about keeping to the shadows, or whether Sandra or Bill saw me. Let them see. Both of them.

Up in my room, I closed the door with a feeling of barricading myself away from the rest of the house. As the curtains drew themselves robotically over the windowpane, my last glimpse of the outside world was of the bloody streaks of sunset fading behind the far-off peaks of the Cairngorms, and of a light in Jack’s window shining steadfastly across the darkening courtyard.

I thought of him, as I let my head sink into the goose-feather softness of the pillow. I thought of his hands that morning, the ease with which he restrained the two excited dogs, the way he dominated them, keeping them at heel. And I thought of the key, and how he had gone unerringly to the place where it had been hidden, a place I had already checked.

But then I remembered other things—his kindness that first night, in coming to check on me. And his voice over the baby monitor, putting Petra to sleep, crooning to her with a gentleness that made my stomach clench in a strange way I could not pin down. There had been no deception there. No pretense. That gentleness was real, I was certain of it.

And I wondered, if it had been him in the kitchen that night, instead of Bill, would I have lurched queasily from the room with panicked disgust? Or would I have reacted very differently? Opened my legs to his, perhaps. Leaned forward. Blushed.

But even as the thought came to me, making my cheeks flush in the darkness, I remembered again, kneeling on the floor of the utility room, sweeping my phone torch beneath that washing machine. That key had not been there. The intervening hours had not made me doubt that fact anymore—quite the reverse. I was totally sure now.

Which meant . . .

I rubbed my hands over my face, resisting the urge to scratch the fading itch left by the creeper. I was being absurd. There was no earthly reason why he would steal that key simply to unnerve me. He had his own set, after all, and his thumbprint was authorized for use on the front door. (Though . . . there was probably a record every time someone used that lock, my subconscious whispered. A record that wouldn’t exist with an old-fashioned lock and key.)

But no. No. It made no sense. Why would he go to the trouble of making a key disappear for a few hours? What would he gain from it? Nothing, except to put me on my guard. And there was my necklace too—my necklace, which I had still not found, though I’d not had time to look properly. That could not have been Jack, surely. This was paranoia, all of it. Things get lost all the time. Keys fall down. Necklaces get tidied away into pockets and drawers, and unearthed days later. There would be a perfectly reasonable explanation for all of this—one that did not require a conspiracy theory.

I pushed the thought down as I rolled over and let sleep cover me like a heavy blanket.

My last thought, as sleep claimed me, was not of Jack, nor of the key, nor even of Bill. It was of the footsteps in the attic.

And the old man who had lost his daughter to his poison garden.

There was another little girl.

My hand went vainly to my throat, trying to hold a necklace that wasn’t there. And then at last I slept.

I woke to the sound of screams and a confusion so loud that my first instinct was to clap my hands over my ears, even as I bolted upright in my bed, staring wildly around, shivering with cold.

The lights were on—all of them, turned up to their brightest, most eye-searing maximum. And the room was icy-cold. But the noise—Jesus, the noise.

It was music, or at least I supposed so. But so loud and distorted that the tune was unrecognizable, the howling and squealing coming from the speakers in the ceiling turning it into a formless din.

For a minute I couldn’t think what the hell to do. Then I ran to the panel on the wall and began pushing buttons, my pulse pounding in my ears, the screeching misshapen music like a howl in my head. Nothing happened except that the lights in the closets turned on to join the rest.

“Music off!” I shouted. “Speakers off! Volume down!”

Nothing, nothing.

From downstairs I could hear furious barking, and terrified steam-train shrieks coming from Petra’s room, and at last, abandoning my attempts with the panel, I grabbed my dressing gown and fled.

The music was just as loud outside the children’s rooms—louder even, for the narrow walls of the hallway seemed to funnel it. And the lights were on down here too, showing me a glimpse of Petra through the nursery doorway, standing up in her cot, her hair tousled on end, screaming in fear.

I snatched her up and ran to the girls’ room at the end of the corridor, shoving the door open to find Maddie curled in a fetal position in her bed, her hands over her ears, and Ellie nowhere to be seen.

“Where’s Ellie?” I bellowed, above the noise of the music, and Petra’s fire-engine wails. Maddie looked up, her face blank with fear, her hands still clapped over her ears, and I grabbed her wrist and hauled her to her feet.