A lot like falling by komodobits || Dean & Castiel
Title: A lot like falling on livejournal and ff.net. Also available in pdf and as epub and mobi.
Warnings (from the author): Reference to non-pairing character death, self-harm, some dub-con, Dean being a whiny bitch.
Summary (from the author): Post-Swan Song AU. It’s just your run-of-the-mill monster hunt until Castiel suddenly powers down and loses all his mojo faster than a hooker siphoning petrol from the back of a customer’s truck. Completely lacking any sort of answer as to what the hell is going on, Team Free Will hole up within the safe confines of Bobby’s house, where at the very least there are books, tools, and a steady supply of peppermint tea. It’s pretty damn inconvenient, to be honest - Dean’s already got enough on his plate trying to work out his place in the aftermath of a very anticlimactic Apocalypse, without also having to babysit an angel who is on a daily basis growing ever weaker, sicker, and, by all indications, gayer than a maypole — thanks to Sam’s musical influence. However, as freak snowstorms pin them in place, and as days turn into weeks with no new answers, there are certain truths which must be confronted: that Dean’s frustration runs deeper than cabin fever, that there is a darkness inside Castiel rattling to rear its ugly head, and that the evil seeping into every crevice and corner of Bobby’s house is only getting started.
Review: It's not possible to read this story without physically reacting to it in some way. This fanfiction will make your heart clench painfully and laugh out loud at other times (especially when Cas it trying to tell a joke). It's domestic but not fluffy. I could never know what happens next. All characters are very much in character. At certain times you feel the strong urge to punch Dean, but at the same time, you can understand him. I like how the author managed to portray the characters in a way that they don't appear to be flawless people, but you'll never stop caring about them. A great, thrilling story.