Don't Look in the Basement 1973
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 in charge and not very eager to have her working there. Charlotte finds her job hard as the patients torment and harass her at every turn. But that’s only half of it as Charlotte slowly discovers that Dr. Masters is not who she says she is for the whole asylum has been taken over by the patients bent on murder and mayhem, and Masters turns out to be one of them.