"I reckon there's been a lot of chaps in our position, down across the years. Makes you wonder, doesn't it? Makes you wonder how much of the world is true." —Fred Abberline, From Hell

Writers never let the facts get in the way of a good story. If reality doesn't fit the plot, it can be changed. History and myth are the most common targets of this - it's much easier to convince the viewers that a 9th century pope was actually a woman disguised as a man than that the current pope is female.

When this Reality Retcon is a story premise Plausible Deniability is generally the aim, but the retcon remains a clear, deliberate, and direct contradiction of generally accepted facts.