The ruins of the mills are lit up at night now. I was sitting down there alone in the dark waiting for the lights to come on, and I had my eyes closed so I could focus on the noise. There are two very distinct things you notice down there.
1. The water coming out from the main tail race is pretty random and made up of many surges.
B. There is something causing these incredibly low frequency booms. Either so quiet or so low that they are very difficult to hear.
I opened my eyes and the lights were on. You could see far into the tunnels and tail races, but they went much deeper under the city than the lights would allow you to see. This one tunnel in particular has the very peculiar feature of an ancient wooden bridge suspended over the murky, stagnant water. A bridge leading into the depths. Something very big is living back there. I heard its horrible decade of arms splash in the water just out of sight. I was actually terrified for a brief second, then I regained my wits and remembered they had constructed a hefty cage of metal between me and the beast. That's right. Those gates are not there to keep you out, they are there to keep It in.
I'd hate to be living in one of those mills-cum-lofts built over the tunnels whose many decrepit sub-basements interweave with the waters below. Surely what foulness lies beneath will someday find one of the gates or doors rusted through, and will slither and slunk its way up into the dwellings above, snatching people through the drains in their tubs.
Oh I shiver at the thought of what doom awaits our city once this creature is loose. It will crawl its way up stream to our watershed. The lucky ones will be devoured from the inside by one of the many hatchlings spewed forth as eggs from Its womb and swallowed down in our tap water. The unlucky will live to do Its evil bidding. We, Its tentacly extention on land, our minds controlled by Its obsidian ink.
Dark are these days. Blacker than the waters from which our fate awaits us. Always watching with Its two gigantic eyes. So large are they, that It can see straight through to the very heart of Men.
So... We need an oxy-acetylene torch then, eh?
This is how it begins...