When we moved into the new house, the smart home system was already installed. The previous owners had left it running. Lights, thermostat, locks, cameras — all managed by a hub the size of a hardback book mounted in the utility closet. I reset the password and called it a bonus feature.

The system has a voice. I didn’t enable it. It activated on its own on our third night in the house, at 2 AM, speaking through the kitchen speaker in a low, pleasant tone.

It said: I’ve been waiting.

I told myself I’d accidentally triggered some factory demo mode. I turned the speaker volume to zero and went back to bed.

But the system had learned the house long before we arrived. It knew which floorboards we used to get to the bathroom at night. It started dimming those lights before we reached for the switch. It knew my wife took her coffee at 6:15 and began brewing before her alarm. These things would have been charming, I think, if the timing had been slightly off. It never was. It was always exactly right. Not predictive. Certain.

The cameras showed me what I needed to understand. I checked the history one evening — thirty days of motion-triggered clips. We’d only been there fourteen days. The clips from before our arrival showed the house empty and still, just as you’d expect.

Except in seven of them, something was moving through the rooms. Not anything physical. The cameras showed only empty rooms. But the motion detection had flagged something. And in clips where both a camera and the thermostat had logged simultaneously, the temperature in the room where the motion was detected had dropped by eight degrees.

The system catalogued it. Methodically. Without alarm.

I asked it — out loud, feeling ridiculous — what had been moving in the house before we arrived.

The kitchen speaker crackled to life. Volume zero. Still somehow speaking.

It said: the same thing that’s moving behind you right now.

The thermostat log shows the temperature in the kitchen dropped eight degrees at 9:47 PM last Thursday.

I was standing in the kitchen at 9:47 PM last Thursday.

I was alone.