So, I amused myself a little too much writing a bio for the Warhammer Fantasy Roleplay scenario that I have decided to run at this year's UK Games Expo...
When the Bretonnians first came here, this was all swamp. Everyone said it was daft to build a grail chapel on a swamp, but the Lady of the Lake demanded they build it all the same, just to show them. It sank into the swamp. So the Bretonnians built a second one. And that one sank into the swamp. So the Lady decreed they build a third. That one was gutted by fire, razed by demons and lost to the mists of the swamp.
Then the King did venture forth and say, "There's an old saying in Quenelles - I know it's in Brionne, probably in Quenelles - that says, fool me once, shame on - shame on you. Fool me - you can't get fooled again."
And that was that for building grail chapels in the middle of forlorn swamps, for the King had a way with words that brooked no further arguments and the Lady was silent.
Even the bravest of Bretonnia's questing knights have not been able to reach the ruins of the Chapel de Marais, where precious relics of the the Lady of the Lake are said to reside. Instead there are tales of lost knights crossing swords with the swamp's one-eyed demons and being stimied by the magic fog they wield.
Surely your rag-tag group of ne'er-do-wells led by an errant knight will succeed where the cream of Bretonnia failed? Surely there is nothing odd about the aging castle that lies on the edge of the swamp, with its equally decrepit Castellan and his beautiful daughter.
Warning: Scenario may include outrageous French accents and oppression of peasants. But not too much quoting from That Film.