A wishing well is nothing more that a place to hope and dream. A token offering is given with the silly notion that the wish just might come true. But what happens when these wishes start to come true, on a regular basis?
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.