I've been trying to find a story that I read and loved for a few days now, I know which one it is but for the the life of me I can't remember the name of the author or the name of the story to find it again...

The fic starts with Sam at Stanford, he lives with Jess I'm sure and then he disappears. I can't remember correctly if she calls Dean and John but somehow they all get in touch and they begin to try and find Sam. When they do find him he's quite insane and confused & has a damaged arm/hand. As the story progresses they find out that an angel showed Sam the future (where Jess and John died) and he left to try to change that. As a result of this Sam sees both timelines, the one where everyone is alive and the one where Jess and John died so he has difficulty distinguishing between the two...

If anyone knows which story I'm talking about I'd be very grateful if you can link me :D