A group of college students, led by Claudia, decide to investigate a local tower that has figured prominently in disturbing reoccurring dreams Claudia has been having. They are suspended from school for their antics, but Claudia learns from one of the female staff members that the person in the dream is a student who killed herself years before and that the headmistress has seen her ghost.
Sister Maria is known in the convent for her good works and charity, but, in the secret depths of her sexual fantasies, she is tormented by visions of another world - a world where her forbidden passions are allowed to run free. In this world Satan is her master. As her acts of violence and blasphemy mount, Maria realizes that she has been chosen by the Devil to destroy the convent and lead her sister nuns into hell!
Alberto Medina is a famous composer whose car breaks down while he is on a trip. While looking for help, he finds the Valverdes' house and is welcomed in by Emilia, the mother of the family, who is known for taking in tramps.
