The Shattered Circle

The Shattered Circle is an AD&D® adventure for four to six player characters of 1st to 3rd level. For many ages, the standing stones known as the Circle of Cahervaniel have stood on a grassy hilltop, unremarkable and unmenacing, but something has changed. A powerful artifact deep within the earth has been uncovered, and its evil power has corrupted the recent inhabitants of a dungeon complex. The chitine live within, a cross between humans and spiders created by the drow, but trying to live a quiet existence. The evil Foundingstone has corrupted some of the chitine, and split their society in two, bringing them to conflict. Adventurers who navigate the chitine factions and dangerous dungeon will need to end the threat of the Foundingstone and the solve the mystery of the strange dark unicorn Mizar that has appeared recently around the stones.

Interestingly, one of the unique magic items in this adventure, Icerazor - is said to have grown from a shard of Frostrazor, a sword that appears in a famous later adventure - Return to White Plume Mountain. There is a brief mention of Suloise, so it can be considered a Greyhawk adventure, but clearly states it can be placed anywhere.