Alternate version of the morning after that fateful Nightmare Night, and ending with the two (plus one) going on a trip to an interesting place recommended by a certain timey-wimey pony.
 
In this AU, Time Turner and Doctor Whooves are the same, specifically, the Tenth Doctor at some point between “Journey’s End”/“The Day Of The Doctor” and “The End Of Time”
 
EDIT: I’m making it official that the punchline is that, instead of a vacation, they find yet another potential suicide mission waiting for them. Because Rule Of Drama.