During the summer of 1978, two couples decide to go to a remote vaction house in the north of Spain. Hidden away in the middle of a forest, and very much off the beaten track, the house seems ideal for some peaceful holidays. While out hunting, the two men come across an abandoned house and discover a deformed, animalistic girl chained inside. They bring her back to the house, intending to take her to the authorities. Tension mounts with the locals...