Universal Constants

Dean had a decent life. He had an awesome little brother, and even if his parents are a little distant now what's there to complain about? Except...then he meets Castiel. And even though he knows it's impossible, Dean has the nagging feeling that he's met Cas before. And then Dean wakes up. And the whole cycle starts all over again. T for Dean's foul mouth. (On Hiatus, sorry!)