Young doctor Garondet is summoned by renowned Professor Orloff. At Orloff's castle, Garondet discovers that the mad scientist has created an invisible yet murderous apeman.
| Actor | Role |
|---|---|
 Howard VernonProfessor Orloff | Professor Orloff |
 Brigitte CarvaCécile Orloff | Cécile Orloff |
 Fernando SanchoThe Game-Keeper | The Game-Keeper |
 Paco ValladaresDr. Garondet | Dr. Garondet |
 Eugène BerthierThe Old Servant | The Old Servant |
 Isabel del RíoMarie | Marie |
| AArlette BalkisNot listed | Not listed |
| MMay ChartretteNot listed | Not listed |
| CChristian ForgesNot listed | Not listed |
 Evane HanskaThe Servant | The Servant |