A brilliant scientist who has lost his memory is hunted by Communist agents out to obtain a secret formula.
| Actor | Role |
|---|---|
 Derek FarrIvan Mason / Dr. James Paxton | Ivan Mason / Dr. James Paxton |
 Ella RainesRhona Ellison | Rhona Ellison |
 Donald WolfitProf. Cattrell | Prof. Cattrell |
 Lisa DanielyNurse Mitzi | Nurse Mitzi |
 Bruce BeebyDr. Manning | Dr. Manning |
 Russell NapierScotland Yard Supt. Davidson | Scotland Yard Supt. Davidson |
 Cyril CusackDr. Kelly | Dr. Kelly |
 Frederick PiperMedwood Inspector Hayman | Medwood Inspector Hayman |
 Karl StepanekDmitri Balinkev | Dmitri Balinkev |
| AAlfred MaronAmbulance Driver | Ambulance Driver |
 John WelshGeorge White - the Gamekeeper | George White - the Gamekeeper |
| OOlive SloaneMrs. Lemmin - the Landlady | Mrs. Lemmin - the Landlady |