The Halls of Cauldron Mountain

From the publishers blurb: Travel to an ancient volcano overrun with purple worms wher ecults to dragons and halls to Dwarven gods once stood. As you delve deeper and deeper, a passage to Cthonia, the twisting and turning maze of subterranean tunnels might even be uncovered...but first you must survive the Halls of Cauldron Mountain! This module is free of licensing and may be shared, modified, and altered as you wish.