Palace of the Vampire Queen was the first published stand-alone adventure module for Dungeons and Dragons (although it predates use of the term "module" and was instead known as a "Dungeon Master Kit"). Although it was not created by TSR, the module was distributed by the company for a short time. Because of the product's unique position in RPG history, and its relative scarcity, the supplement is considered highly collectible.
The plot of the module concerns a female vampire who has kidnapped a Dwarven princess. The PCs, naturally, are charged with the princess's rescue. In order to do so, they must contend with the denizens of the eponymous Palace, which include vampires (obviously), screech owls, and a madman with a horde of devilish house-cats.