Doctor Who: Series 9 Episode Titles And Plots Announced
9. Episode 4: Before The Flood
Here's another new title: Before the Flood. The "flood" would appear to be the cause of the lake in the preceding episode.
So, what was waiting under the lake in episode 3? From the image associated with the story summary, the Fisher King, presumably (and there's a Grail-related name). Again, the new details from Moffat confirm this piece of Doctor-y dialogue heard in the series trailer is from this story:
"Doctor. Hello. Can I just say: huge fan."
He can only be talking to the Fisher King. From the following summary, it seems as if this story is set in the past:
In the eerie remains of a town that never was, something is stalking the Doctor and his friends. A desperate battle for survival is underway, but this time our heroes already know which of them is going to lose. With the past and the future hanging in the balance, the Doctor is breaking the rules to win the day. Can anything stop the Fisher King? And more importantly, who composed Beethoven’s 5th?
My guess is that all record of the town was wiped out by the events of this story, meaning that by the time of the previous episode no one remembered it any more. Also, the "breaking the rules" part sounds like the Doctor is trying to alter established history. Yeah, that always turns out well.