“...And you, Human, must follow our words, lest we summon up every curse that lies buried beneath these sands and pour them upon you and your children, and their children, and in turn their children, for so many generations that your blood will surely never survive.”
Under the sewers of a large town ancient burial chambers are discovered. If the PCs investigate they fill find that a pale white flowers grows amongst the graves, in the dark.
How do they survive without light? What is their origin? Why in a burial chamber and not just in any old cave?
Can they be sold or do they have any special quality at all? It is up to the PCs to discover.