London is an old, old city, dating all the way back to the days of Rome and, perhaps unsurprisingly, its full of old, old magic. Besides housing the headquarters of the wizard Council of St Albans, it also bosts the Under Parliament, which governs the affairs of the White and Red vampires of Britain; hell, the Seelie and Unseelie fairy courts both have representation in the bustling metropolis, their efforts bankrolled by the children of a Persian dragon.
But London isn't just an old city, but also one of new ideas and innovations; it's home of the club Mirror, Mirror, which is recognized as neutral grounds for all supernatural parties, as well as home of the Free Court of London, a fairy court that recognizes no authority but it's own. In the abandoned graveyards, the Black vampires hide and organize under the self styled High King of the Rippers, striking terror into the hearts of those who know what danger lurks in the dark.
Atop all this sits the mundane world, which does its best to ignore the supernatural beings that inhabit it, but, when that can't be helped, the Special Tactics Occult Group is only a call away, ready to bring order and mundanity with them.
This, then, is London, both mythic and mundane, old and new. And everything's about to start falling down.
NOTE: While we use the rules provided by the Dresden Files RPG, we have made the conscious choice to not set the game within the Dresdenverse, mostly because no one but the GM has read the books.