The Third-Floor Buttons Press Themselves at 4 A.M.

I run the night desk in an office tower, twenty-two floors, and my domain between midnight and six is a bank of monitors and a system log that records every door, every lift call, every card swipe in the building. On a good night it's the most boring job in the world, and I like boring.

The third floor has been sealed for renovation for over a year — stripped, dark, hoarded off, the lift programmed not to stop there, the floor a dead zone on my monitors showing nothing but a locked hoarding and the occasional skittering shadow of dust. Nobody's been up there after hours in months; the day contractors leave by five and the floor is locked down for the night.

Every night at 4 a.m., the third-floor lift call button presses itself.

I see it on my panel: the call light for floor three, illuminating, at 4 a.m., give or take a minute. The lift, which is programmed to skip three, doesn't go — but the call registers, and the log records it, cold and specific: 'Lift call, floor 3, 04:00,' night after night, a request to descend from a sealed dark floor where there is no one to press a button, logged by a system that does not lie and cannot be fooled by a draught.

I did the diligence. Checked the wiring with the day engineers, who found nothing. Watched the third-floor lift lobby on the one camera that still covers it — the feed shows the dark lobby, the call button, and at 4 a.m., the button lighting up, pressed, with no one in frame, no movement, nothing, just the button depressing itself in an empty sealed lobby and the call registering on my log. I have the footage. The day staff have seen it. Nobody has an explanation and the renovation, tellingly, keeps falling behind because the contractors, I've gathered, don't love that floor.