Summer 1978: two couples decide to spend the summer in a remote vacation 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 with the rural locals heightens when they come looking for the girl armed with shotguns...