Dr Sánchez Blanch owns and operates a psychiatric hospital where he specializes in hypnotizing his severely emotionally disturbed patients. When Beatriz Vargas accepts a position as a nurse in the institution, she quickly befriends a young girl who has been unable to communicate for years due to severe shock. Although she feels a strong bond with the young girl, Beatriz soon becomes very unhappy with the way the patients are being treated. Her unhappiness begins to result in conflicts with her superiors and co-workers, some of whom may prove to be more dangerous than she first realized. The nurse begins to suspect that she is dealing with something much worse than disgruntled coworkers; that her actual survival may be at stake. After a horrible death occurs at the facility, a man named Miguel poses as a police officer to get close to the inner workings of the hospital. Miguel befriends Beatriz and warns of the terrible danger that may be closing in on her.
