Dark Sun 3.5 - The Lost North
They all grew up somewhere in the Tablelands and believed they knew everything there was to know about "the world." Mul former slave, Villichi druidess, Forest Ridge halfling, and racist human roughian – they all ended up in a particular bar in Draj.
And that's when they started their education about the forgotten regions north of the Tablelands.
This campaign is set in Athas, the world of the Dark Sun and we are using the rules for 3.5 edition.