A masked killer stalks an institution for mentally disturbed rich women.
| Actor | Role |
|---|---|
 Klaus KinskiDr. Francis Clay | Dr. Francis Clay |
 Margaret LeeCheryl Hume | Cheryl Hume |
 Rosalba NeriAnne Palmieri | Anne Palmieri |
| JJane GarretMara | Mara |
 John KarlsenProfessor Osterman | Professor Osterman |
 Gioia DesideriRuth | Ruth |
| GGiangiacomo EliaThe Gardener (as John Ely) | The Gardener (as John Ely) |
 Monica StrebelNurse Helen | Nurse Helen |
 Fernando CerulliChaffeur | Chaffeur |
| SSandro RossiPoliceman | Policeman |
 Giulio BaraghiniPoliceman | Policeman |
 Ettore GeriInspector | Inspector |
| AAntonio RadaelliPoliceman | Policeman |
 Carla ManciniNurse | Nurse |
 Franco MarlettaMale Nurse | Male Nurse |
| PPiero NistriCheryl's Husband | Cheryl's Husband |
| DDaniela Di BitontoPatient | Patient |
 Enzo SpitaleriRuth's Husband | Ruth's Husband |
 Marco MarianiMale Nurse | Male Nurse |
 Gilberto GalimbertiPoliceman | Policeman |
| RRosanna BraidaPatient | Patient |
| LLina FranchiNurse Killed with Scythe (uncredited) | Nurse Killed with Scythe (uncredited) |