A mute young woman is stalked by a serial killer at her uncle's mansion.
| Actor | Role |
|---|---|
 Jacqueline BissetHelen Mallory | Helen Mallory |
 Christopher PlummerDr. Joe Sherman | Dr. Joe Sherman |
 John Phillip LawSteven Sherman | Steven Sherman |
 Sam WanamakerLieut. Fields | Lieut. Fields |
 Mildred DunnockMrs. Sherman | Mrs. Sherman |
 Gayle HunnicuttBlanche | Blanche |
 Elaine StritchNurse Baker | Nurse Baker |
 John RonaneDr. Rawley | Dr. Rawley |
 Sheila BrennanMrs. Oates | Mrs. Oates |
 Ronald RaddOates | Oates |
| HHeather LoweBlind Girl | Blind Girl |
 Christopher MalcolmPoliceman | Policeman |
| HHarry Van EngelPolice Photographer | Police Photographer |
| TTina SimmonsNot listed | Not listed |