Escape from the Astral Spellhold

Publisher's blurb: Designed to be used with any official version of D&D or any of the OSR retroclones. Party level doesn't really matter but it was mostly written with low-level characters in mind. The Astral Spellhold is a short (should last about one session) puzzle dungeon ideal for one-shots, kicking off a new campaign, or introducing an underlying conspiracy to an ongoing campaign.