Nurse Charlotte Beale arrives at the isolated Stephens Sanitarium to work, only to learn that Dr. Stephens was murdered by one of the patients and his successor, Dr. Geraldine Masters, is not very eager to take on new staff. Charlotte finds her job maddeningly hard as the patients torment and harass her at every turn, and she soon learns why Dr. Masters is so eager to keep outsiders out.
Dr. Patrick "Pat" J. Cory is researching brains with his assistant and friend Dr. Frank Schratt and his wife Janice Cory through experiments with monkeys in a laboratory in his house.
Dr. Henry Jekyll experiments with scientific means of revealing the hidden, dark side of man and releases a murderer from within himself.
Aboard a British train, mysterious fortune teller Dr. Schreck uses tarot cards to read the futures of five fellow passengers.