The Heart of Glass is a dark adventure that pits the party against thieves, assassins and other denizens of the night. It takes place in the back alleys and abandoned neighborhoods of the Sea Towns of Ihlsa. There, amidst the twisted, jumbled streets of the Three Cities, one can buy anything, or anybody, for a price. The party must penetrate this reclusive world and unravel its mysteries in order to upset the plans of Malcom of Helliwell and retrieve the magical artifact which Malcom so ardently desires.