Nurse Beatriz Vargas arrives at a remote psychiatric institution where Dr. Sanchez Blanc experiments with hypnosis. Beatriz soon becomes the first person in years to communicate with a child who's been in shock since her arrival. Other inmates include kindly Ulloa and the psychopathic Miguel.Beatriz's unhappiness with the hospital's methods, however, provokes conflicts with Dr. Zabala. Meanwhile, alcoholic nurse Elena, who sleeps with the patients, also becomes a dangerous opponent. When the child kills herself, Miguel, claiming he's a policeman sent to investigate, warns Beatriz that it was not suicide and that she should watch out for herself.