Fu Manchu abducts a missionary doctor and forces him to surgically turn one of his hypnotized dacoits into a murderous doppelgänger of his arch-nemesis Inspector Nayland Smith of Scotland Yard as, part of a plan to become leader of the World's criminals
| Actor | Role |
|---|---|
 Christopher LeeDr. Fu Manchu | Dr. Fu Manchu |
 Douglas WilmerNayland Smith | Nayland Smith |
 Horst FrankRudy / Ronald "Ronny" Moss | Rudy / Ronald "Ronny" Moss |
 Tsai ChinLin Tang | Lin Tang |
 Wolfgang KielingDr. Lieberson | Dr. Lieberson |
 Maria RohmIngrid Swenson | Ingrid Swenson |
 Howard Marion-CrawfordDr. Petrie | Dr. Petrie |
 Suzanne RoquetteMaria Lieberson | Maria Lieberson |
 Noel TrevarthenMark Weston | Mark Weston |
| TTony FerrerInsp. Ramos | Insp. Ramos |
| MMona ChongJasmin | Jasmin |
 Peter CarstenKurt Heller | Kurt Heller |
 Eddie ByrneShip's Captain | Ship's Captain |
 Christopher CassonNot listed | Not listed |