Two couples(and their adorable dog) are on their way to a skiing holiday, when they stop off for the night. The two men Roger(Peter Fonda) and Frank(Warren Oates) notice some strange goings on and soon realise they are witnessing a full scale satanic ritual complete with human sacrifice. They are spotted by the satanists, but manage to get away. They arrive in a nearby town, and the two men return with the police to the scene of the crime, whilst the women(Loretta Swit and Lara Parker) stay behind, only to find an occult spell pinned to their vans back window. Soon they are being pursued across America by the unstoppable Devil worshippers.
This is a great 70's film, part road movie, part horror movie, and full enjoyment factor. It is a very creepy film, as the foursome start to realise how far the influence of the cult reaches and how much danger they are in. This being a 1970's film the couple are very fond of eachother and unite against the peril they face(if this was made now, they would probably all be sleeping with eachother, and bitching constantly). The ending is the highpoint, shocking and abrupt. There must have been a few gasps from the audience when it was originally shown. The performances of the main four protaganists are uniformally good, and theres nice support from R.G Armstrong as the local Sheriff.
So, an excellent film, as good as I remembered it from watching it in the early 80's. 4 out of 5