I let my hand fall to my side, breathing heavily but triumphant. Then I set about trying to open the locked door.

First I tried the key to my bedroom door, which Sandra had shown me, tucked away on the doorframe above the door, like the others. It didn’t fit.

Then, I tried the key to the wardrobe on the other side. It didn’t fit either.

There was nothing above the doorframe except a little dust.

Finally, I resorted to kneeling down and peering through the keyhole, my heart like a drum in my breast, beating so hard I thought I might be sick.

I could see nothing at all—just unending blackness. But I could feel something. A cool breeze that made me blink and draw back from the keyhole, my eye watering.

It was not just a cupboard inside that space. Something else was there. An attic, perhaps. At the very least, a space big enough to have a draft and a source of air.

The footsteps had stopped, but I knew that I would not sleep again tonight, and at last I wrapped my duvet around myself and sat, my phone in my hand, the overhead light blazing down on me, watching the locked door.

I don’t know what I was expecting. To see the handle turn? For someone—something—to emerge?

Whatever it was, it didn’t happen. I just sat there, as the sky outside my window began to lighten and a thin lemon-yellow streak of dawn crept across the carpet, mixing with the artificial light from above.

I felt nauseous with a mix of fear and tiredness, and dread of the day ahead.

At last, when I heard a low fractious wail come from downstairs, I loosened my grip on my phone, flexed my stiff fingers, and saw that the display said 5:57 a.m.

It was morning. The children were waking up.

As I crawled from my bed, my hand went up involuntarily to touch my necklace—but my fingers grazed only my collarbone, and I remembered that I had taken it off that first night, spooling it on the bedside table, just as I had done before the interview.

Now, I turned to pick it up, and it wasn’t there. I frowned and looked down the back of the little nightstand. Nothing. Had Jean McKenzie tidied it away?

The wail from downstairs came again, louder this time, and I sighed and abandoned the hunt. I would look for it later.

But first I had to get through another day.

* * *

Coffeemaker—preloaded with beans and connected to mains water. Operated via the app, select “Appliances” from the menu, then “Baristo” and then choose from the preprogrammed selections or customize your own. If beans logo shows, the hopper needs to be refilled. If the ! error logo shows then there is either a Wi-Fi issue, or a problem with the water pressure. You can program it to dispense at a particular time every day, which is great for mornings, but of course you must not forget to put a cup underneath it the night before! The preprogrammed selections are as follows—

Jesus. I had confined myself mostly to tea since getting here, mainly because the coffeemaker was so extremely intimidating—a chrome beast of a thing covered with buttons and knobs and dials. Sandra had explained when I arrived that it was Wi-Fi enabled, and app-operated—but Happy was proving to be the least intuitive system I had ever encountered. However, after my sleepless night, I had decided that a cup of coffee was the only thing that was going to make me feel halfway normal, and while Petra chewed her way through a dish of mini rice cakes, I had resolved to try to figure it out.

I hadn’t even switched it on when a voice behind me said, “Knock, knock . . .”

I jumped and swung round, my nerves still jangling with the traces of last night’s stale fear.

It was Jack, standing in the open doorway to the utility room, jacket on and dog leashes in hand. I had not heard him come in, and evidently my shock and ambivalence must have shown in my face.

“Sorry, I didn’t mean to make you jump. I did knock, but you didn’t hear, so I let myself in. I’ve come to collect the dogs for their walk.”

“No problem,” I said, as I turned to take away Petra’s rice cakes. She had stopped eating them and was mashing one into her ear. Jack’s unexpected presence at least answered my question about whether I was also responsible for the dogs, and was one thing I could tick off my list. Claude and Hero were gamboling around, excited to get going, and Jack hushed them sharply. They fell silent at once, noticeably more quickly than they had obeyed Sandra, and he grabbed the collar of the largest one and began clipping on its lead.

“Sleep well?” he asked casually, as the lead slipped into place.

I turned, my hand frozen in the act of wiping Petra’s face. Sleep well? What did that mean? Did he . . . did he . . . know?

For a minute I just stood there, gaping at him, while Petra took advantage of my momentary lapse of attention to grab a particularly soggy rice cake and mash it into my sleeve.

Then I shook myself. He was just asking in the way people do, to be polite.

“Not particularly well, actually,” I said, rather shortly, wiping my sleeve on the dishcloth and taking Petra’s rice cake away from her. “I couldn’t find the key to the back door last night, so I couldn’t lock up properly. Do you know where it’s gone?”

“This door?” He jerked his head towards the utility room, one eyebrow raised, and I nodded.

“There’s no bolt on it either. In the end I wedged it with a bit of wood.” Though much good it had done. Presumably Jack had simply shoved the wedge aside without even noticing when he opened the door. “I know we’re in the middle of nowhere, but it didn’t make for a very comfortable night.”

That and the sound of footsteps, I thought, but I couldn’t quite bring myself to tell him about that. In the cold light of day it sounded crazy, and there were too many alternative explanations. Central heating pipes expanding. Joists shrinking as the roof cooled from the heat of the day. Old houses shifting. In my heart of hearts, I knew that none of those fully explained the sounds I had heard. But I didn’t know how to convince Jack of that. The key, however, was different. It was something clear . . . and concrete.

Jack was frowning now.

“Sandra usually keeps the key on the doorframe above. She doesn’t like to keep it in the lock in case the kids mess around with it.”

“I know that.” There was an edge of impatience in my voice that I tried to dampen down. It was not Jack’s fault that this had happened. “I mean, she told me that. It was in the binder. And I put it up there yesterday, but it’s not there now. Do you think Jean could have taken it?”

“Jean?” He looked surprised, and then gave a short laugh and shook his head. “No, I don’t think so. I mean, why would she? She has her own keys.”

“Someone else then?”

But he was shaking his head.

“No one comes up here without me knowing about it. They couldn’t get through the gate for a start.”

I didn’t remind him that Jean had found the door locked when I came back from looking for Maddie and Ellie. I hadn’t locked it. So who had?

“Maybe it fell down somewhere,” he said, and went back through to the utility room to look, the dogs following like faithful shadows, sniffing around as he pushed aside the dryer and peered under the washing machine.

“I already looked,” I said, trying to keep irritation out of my tone. And then, when he didn’t straighten up or deviate from his search, “Jack? Did you hear me? I checked everywhere, even the bin.”