Lost Oasis: A Playtest Tale

From the introduction:

After counting yourselves lucky not to have suffered an ill-fate at the battle outside of the Storm Spire, a mysterious tomb-delving Moonshadow elf named Feathershawl (they/them) has commissioned your rag-tag crew to investigate an abandoned city floating high across the Xadian sky. The island is on a collision course with a mountain range at the border, and the clock is ticking to salvage a rare artifact from it; you don’t have time to do your own research before you leave. Hopefully Feathershawl is trustworthy!