The movie is about a woman who goes up to some mountain village with her boyfriend, fiancé, whatever, and they are there to climb a mountain. There's a man there who she knew when she was younger (I think they'd had an affair, or maybe he even seduced her, I can't remember). She goes up the mountain and has to stay in some lodge for a short time I think... (I just remember it was dark). I don't remember much after that until they are climbing the mountain, and this man from her past makes some kind of "sacrifice" -- and he dies, I think. The climbers discover the body of a man who had been lost years before, and they bring his body back to the village.

Five Days One Summer