Hi, all! I'm looking for a specific fic I read almost a year ago, but I'm not sure of the title or site it was on.

All I do remember is that it was Sam, Dean, and Castiel on a hunt of sorts (I think some kind of a witch/goddess on a mountain?) and they were trapped by a blizzard. Something went wrong and Cas ended up possessing one or both of them at certain points, then draining his powers on the boys to keep them from freezing to death while they climbed up the mountain to try and kill it. I also remember there being a cave in the final showdown.

I hope this jogs someone's memory! I've been looking for months, but no kind of search has gotten me anywhere ;u; Thank you for any help.

Found thanks to nad_no_ennas! It was I Cleanse The Mirror by Takadainmate