As I was sorting my bookmarks following the previous rec, I stumbled into this fic and ended up reading it again. It's a Arthur/Merlin Modern AU :
Same As It Ever Was, by
corilannam ; NC-17 ; One-Shot ; 7259 words
A/S : When Merlin wakes up, he’s wrapped in Arthur’s arms. It's the single worst moment of his life.
This is the kind of story where your heart break and then heal to end up melting. But it breaks seriously first. This is also a wonderful story regarding how knowing the future can make you do stupid things in wanting to change it, and finally leads you to only making it happen. This is one of the powerful thing about the episode The Crystal Cave, I think. Oh, so, as you can guess, this is an AU with magic.