Greetings! I've been lurking for a bit and now feel comfortable enough to begin posting. I thought I might start with a discussion about a campaign I'm currently running, just to get some thoughts.
I'm familiar with the planescape setting, but not with all of the details, so if my story misses something, or validates some planar point, please be gentle, dear reader 
I'm working with the Campaign setting, but without the other box sets - no Planes of Law, Chaos, etc. I have other books.. Faction War, Planewalker's guide, Well of Worlds.
I ran my beginning adventure last night - here's a quick recap.
My group is searching for a reason why people are vanishing from the Cage. After some exploration, the players discover that a group of Mind Flayer slavers seem to be at blame. A search for them leads to a portal to Pandemonium. There, in a wind filled cavern, the PCs find slave pens holding about 200 beings of all differing races. A leader-Illithid stands next to a small tower, carved to look like a Mind Flayer tentacle. A fight ensues between the party, the mind flayer eventually plane shifts with the tower as the PCs rout the rest of the creatures. A search through the caverns being used by the Mind Flayers results in the PCs emerging on Mount Olympus in the layer of Venya. PCs and their slaves head towards a small township nearby, only discover the "inhabitants" are glassy-eyed and unaware of their surroundings. A detect thoughts check shows that these are former slaves, who believe themselves to be in the Abyss.
The PCs are now in the position to try to rectify this situation while left wondering if this barmy plan could work actually affect the layer, or at least parts of it..
Thoughts?