It’s not what I’ve always assumed is a generator. It’s not in my head either. The first few times, I started to worry that it was – that this was some consequence of my isolation, the start of an illness, except not one that would consume my body, but one that would demolish my mind. That’s something that has troubled me since the very first moment I woke up here. When all you can see is darkness, when most of your time is spent in complete silence, when scenes from your life, faces you’ve pictured or conversations you’ve replayed aren’t real, but imagined – constructed in the space behind your eyes – sudden noises aren’t a reason to rejoice. They’re a reason to be fearful and to panic.

Because you want them to be real.

You’re just terrified they’re not.

This one, though, is different. It feels different. When I clear my head, when I let the portraits of my family go, of my parents, of friends and people I worked with, of every single face I’m using to try and keep me sane, I can still hear the noise. It’s not some remnant of a memory. It’s real. It’s here, as much a part of this place as this floor and these walls are, as I am. When I move, my muscles stiff, my body doughy from the lack of exercise, I can still hear it. When I eat – and the sound of my eating fills my ears – it doesn’t go away.

I need to find out what it is.

I get on to my feet, arms out in front of me, and shuffle forward into the dark, in the direction of where I think it might be coming from. I don’t know how this place looks in the light, if there was ever light here, but I know there must be doors, even though I can’t find them, and I know it’s fifty-two paces north to south and forty-seven paces west to east. I have no idea what’s actually north, south, east or west, but I know which wall is which, so I give them compass points to help me navigate.