The Jade Dagger

From Introduction:

Following is an adventure set in Shadow World, on and about the continent of Emer. It begins in the famous trade city of Kaltaine off the southwest coast, but takes the players to the legendary Isle of Jade. This semimythical island is protected by jagged reefs and cloaked in drifting mists, but its jungles are said to conceal an ancient culture...and fabulous treasures.

Thrust into the middle of an old and deadly rivalry, the players are unexpectedly drawn to this deceptively peaceful-looking isle. There they must choose sides between a prehistoric Dragon Cult and an order of shadowy, fanatic priests.