In a way, it was a LARP that set a good bit of this in motion. Not everything, but it certainly played a part. There was a period of almost 3 years during which I was taking part in a Live Action Roleplaying game based on Neil Gaiman's Neverwhere. I was, in fact, playing a version of Ingress (Ress), the youngest daughter of the the House of Arch, who only appears in the book very briefly and is still missing (and perhaps dead) at the end of it.

She was an Opener, and had a tendency to collect lost keys. I didn't even have to try very hard, as over the course of the game other players would seek me out and hand me bunches of old keys. Sometimes they would want the prop back at the end of the game. Usually they didn't. Then the key acquisition started to bleed out into the real world, and old keys continued to find their way into my possession. I amassed quite a horde of random keys and a desire to find things to do with them.

This key actually did come to me during the course of some Floating Market session or another. So it seems appropriate that when it does eventually leave me, it will also be by way of The Floating Market.