I read this fic a while ago and I've forgotten the name of it and who it was by.

Things I remember;

Sam and Cas were investigating mysterious deaths in a small town. It turned out that everyone was having bad dreams and they were so terrible that they died instead of having to deal with it.. One person actually falls out of a window in front of Sam and Cas. At one point Sam (or Cas) gets infected and they see the other person die but it turns out to be a nightmare. I think there were demons involved too but I'm not entirely sure about it.

Sorry it's so brief but am hoping someone can help me find it.

Thanks in advance.