Miguel, a young man with severe disfigurements, unleashes chaos at a masquerade party, committing a brutal assault and mutilation of a girl. After being confined to a mental institution, he is released five years later into the custody of his sister, Manuela. She and their mother, who is confined to a wheelchair, run a boarding school for young women. Miguel develops an unhealthy fixation on one of the students and desires to rekindle his incestuous relationship with his sister.