From the publishers blurb:
Oasis of Koessa is an adventure set on the Seventh Circle of Hell, the Desert of Fire, can be used as a projection of Hell into the Material Plane, or it can be used as an enchanted location in any remote hot desert. It can represent any of nine Oases found in the Desert of Fire. The Oasis is a dangerous and challenging location suitable for challenging higher-level Adventurers. The non-linear location contains eight significant structures which can be explored in any order, each with different challenges and opportunities. The centerpieces are the two large Pyramids and the dungeon inside a Sphinx statute.
Oasis of Koessa is completely compatible with the Spellbook Games’ epic game module, Journey through Malebolge, and the four Gazetteers of Hell, which together describe the complete Hell of Dante.
Oasis of Koessa is written for Spellbook Game’s Portal to Adventure RPG rule set, but can be used essentially as-is with First Edition Dungeons and Dragons or any similar rules. Games Masters using 3.x, Fourth Edition or Fifth Edition, or any similar rules will have significant conversion work. 55 pages plus Denizens.