this be a good film to watch on a long winter evening . two primate behavior scientist arrive at a mountain top research station to find their predecessor frozen to death under strange circumstance . a they settle in and one of them dwells on the mystery of the frozen colleague and while the other go right to work on the monkey . then they begin to slowly unravel somewhat like jack torrence in the shining . the whole film be hold together nicely by wallach and culp and and the sense of austere isolation be pull off beautifully .