From publisher website: A mysterious castle has appeared on a mountain near the capital city of Zanzia. The king is alarmed by this development and has summoned the best and bravest adventurers in the land to investigate this castle. This is an epic level adventure intended for those characters that are a minimum of 20th level of experience. Powerful new creatures and magic items will be encountered in this adventure. Challenges worthy of those of the highest levels of skill will make this adventure a dangerous one for even the most powerful adventurers.