Time paradoxes and dimensional travel. Someone with knowledge of the future winds up in the past, with a chance to fix things. In science fiction, this often does not turn out well. In the Buffyverse, sometimes it does. Here are three stories about getting to do it over again.
"Everything old is new again" by
Jessie (Giles/Buffy friendship, hints of future romance, FRT):
one and
twoBuffy makes a wish in front of re-demoned Anya. Oh man, never do that in the Buffyverse! She finds herself walking through the library doors in 1997, about to meet her new Watcher. He slams the copy of Vampyr down in front of her... and she gets things off to a better start than she did on her first go-round.
Buffy's relationship with Giles is the core. I love Jessie's depiction of how Buffy's differences as a person affect who Giles is and what he allows of himself to show. Buffy also learns that just knowing one set of bad events in advance isn't enough to save you from all bad things. So Principal Flutie isn't eaten by hyenas this time; something else happened to him. The take on Angel is also excellent: Buffy's older perspective changes her view of Angel's first-season actions quite a bit.
Somewhere in time by
gilesbabe (Giles/Buffy, FRM, unfinished):
one,
two,
three,
four,
five,
six,
sevenThe battle against the First is lost. They are all dead, all of them, except Buffy and Willow. Willow, before she takes the last desperate step to end the First, sends Buffy to a dimension that needs her. And she finds a Giles who has lost his Buffy and everyone else, and sends him there too. Season 7 Buffy finds herself with Season 1 Giles in the living room at Revello Drive, with Season 4 everybody else, griefstricken because their Giles and Buffy have just died. Now what?
Much of the fun is watching Gilesbabe work out the plot here, showing how the battle-hardened older Buffy takes charge of the situation and methodically deals with the situation in front of her, while an unscorched, unscarred naive Giles adjusts. There's an element of wish fulfillment here, but Buffy has to work to avoid the traps they all fell into in her past.
Paradox by Kerry Blackwell (FRT)
There is a prophecy-- isn't there always?-- that Buffy's daughter will save the world. But Buffy's daughter isn't ready to save the world. She goes back in time, to before she was born, to try to fix things so that when the time comes, that daughter will be ready.
A wonderful story, one of the greats in Buffy fanfic, and one of the stories that got me most excited when I discovered the fandom.