Of Storms & Sanctuary by bree_black
The Story: AU from Episode 5.22 Dean becomes almost suicidally reckless after losing Sam, and one day a hunt goes wrong and he ends up in hospital in a coma. Castiel enters Dean's dreams and is surprised at the peaceful little world he finds there.
The Love: The prose of this story sucks you in straight from the beginning, and I love the juxtaposition of the peace and tranquility of Dean's dreamworld and the chaos of reality, because you honestly begin to feel sort of okay with him possibly not waking up and staying in this sanctuary of his own creation. And all the symbolism is so well done. And SAM. And the intimacy between Dean and Cas. And... and... just read it.