I read this story just recently, but for the life of me, I can't remember the name/refind it.
It wasn't super long, in the first part Sam was young and he met a lady or John left him with a lady for a short time who was a good witch who taught him things. He knew his dad and Dean wouldn't approve so he kept it secret. I remember something about crows in the trees of her house or Sam being able to talk to things... not sure if I'm mixing this up
He only met her one more time, but it was a good experience.
Then the story picks up when he's later and I get fuzzy about this, but I think he saved his whole family or maybe it was only Dean by using magic.

Any help finding this with my super fuzzy description would be greatly appreciated. I don't even remember if it was slash or gen.

***UPDATE***
Found by caranfindel it was their wonderful spn_summergen fic: These are the days of miracle and wonder (this is the long distance call)