I've an idea that's a diversion to my usual activities :)
A princess has fallen in love with someone forbidden, maybe a thief, peasant or even a castle servant, but her father has already promised her to a prince in a neighboring kingdom. Not that he would approve a non-royal anyway. She's fourth in line for the throne, so she doesn't see why it matters.
There is fallen king or maybe a dragon, who steals her away and her love is the one who saves her.
I'd need either one person willing to play both villain and the love or two people :)