Planescape (2015)
"Planescape Nights" - The Planescape campaign setting bolted onto Hackmaster 4th ed.
Contents
The Setting
Sigil and the Planes at large. Wherever the story or your own hearts' desires take you.
Sigil
As Sigil is the literal metaphysical center of the planes, and the City of Doors that theoretically contains portals to every conceivable plane, you will find yourself returning to or travelling through it often.
The Planes
I don't believe in having 'a' prime material plane, so you'll find yourself faced with a multiverse of material planes (earthlike or similar worlds). Additionally there are the inner, outer, elemental, etc.. planes of the Planescape setting. Nothing is off limits, if you can learn about it in game and find your way there.
The Story
Epic high fantasy, sword and sorcery, all this and more! Be a wizard pretending to be a cleric! Or whatever you want! We will hit the streets of Sigil and adventure will find YOU. I promise you the finest in improvisational fantasy as you trek across the planes.
You are all adventurers. You could be gallant knights, you could be fire-flinging wizards. You could even be soldiers, but you might not be heroes.