Supernatural - Seasons of Mists
Seasons of Mist by girlupnorth. I can't really think of a good summary for this one, so I'm just going to copy and paste one of the first lines from the story. It’s been two days since Ruby left the Winchesters in Bumfuck, End-of-the-US, when she comes back to her room to find her protective spells broken, and an angel standing by the wall.