As far as the general setting, this will be within the Abraxis sector, which is sort of a blank slate right now.
Back in 2009, Kaled contrived the idea of the Carthax sector (
its wiki is here) as a community setting, which meant that even if there wasn't a direct narrative from one event to the next, there was at least a continuity - and keeping it in a somewhat restricted area also helps explain why the same characters keep running into each other.
Carthax was a brilliant idea, but it's almost exclusively used for 54mm. Abraxis has come along later as a 28mm equivalent, so that players aren't dropped into a setting written by a load of people and featuring a load of characters they'll never get to interact with on the table.
Abraxis borders the Dalthus Sector that The Ammobunker set up, in order that it's plausible for characters from that setting to appear, but the development is being handled on a more ad-hoc basis, keeping the big picture somewhat vague so that it's harder to write things into a corner down the line.
It's yet to get a wiki - partly because it's only been used for three small events so far, and partly because I've yet to decide whether it should be separate from the Carthax one or whether to re-organise the Carthax wiki to cover both and keep all the Inquisitory goodness in the same place.
As far as broad details, it's out towards the Eastern Fringe, there are some sub-sector names (and rough descriptions)...
... and currently it's suffering from being on the fringes of a warp storm (the last event saw the players fail to deflect an oncoming warp storm).
But other than that, it hasn't even really got many planet names or major NPCs set up. People like the sector governor, head of the sector conclave, etc still aren't named. Now that Abraxis is starting to be more used, I'll probably fill in some of the big gaps (once I decide how to handle the wiki), but mostly the intent is to let people add new bits as they're needed.
The event won't be happening on any single world within the Abraxis sector though. Different scenarios will be happening in different places, as Inquisitor Carren has been at large through large portions of the sector, so the evidence both for and against him is widely spread.
