Haunted island
by Cab DavidsonHaunted island, in the marshes in the east of the Alphatian kingdom of Haven (Mystara). The centre of the haunting is a carillon (a keyboard instrument installed in a tower, that plays the bell therein). By playing said instrument the creature (a spirit of some kind that possesses the instrument) can control undead on the island, and every (x) amount of time try to possess one a creature within earshot (in the flat marshes, that might be a mile). The PC's are sent in to find sacred paint brushes that create beauty if the painter is pure of heart, images that repel undead, which previous adventurers brought with them to try to contain the undead entity. Staging is on an island in a marsh, in a strange castle built to resemble a defensive structure in a less civilised nation, so on a larger scale and of little or no value as a fortress, containing the former owners library, museum, various secret passageways for servants to just appear, and a central belfry with the carillon at the base. There's also a village on the island, with locals living in a perpetual state of existential terror. Every time one tries to escape, the entity posesses it and brings it back. Is this too complicated or (as I'm aiming at) a pleasing synergy of horror in an art-obsessed kingdom?
How they resolve it will be to destroy the instrument. The reason for the haunting will be that the lord of the manse did a deal to keep his dying daughter alive or, at least, present on the prime plane with him in some form. That's a detail I need to work on to get the balance between the party having sympathy for him and hating him - to turn this into a fight for survival before laying the trouble dead to rest.