Special investigator Duke Martin is in London to investigate the authenticity of a rare postage stamp called the Barbados Overplate. Someone is willing to commit murder to get his or her hands on the stamp, which puts a crimp in Duke's efforts to romance every beautiful woman he meets.
| Actor | Role |
|---|---|
 Tom ConwayTom Martin | Tom Martin |
 Delphi LawrenceJean Larson | Jean Larson |
 Brian WorthGeoffrey Blake | Geoffrey Blake |
 Michael BalfourBarney Wilson | Barney Wilson |
 Marianne StoneMrs Wilson | Mrs Wilson |
| CCampbell CottsRobert Coburn | Robert Coburn |
 John HorsleyDet. Insp. Taylor | Det. Insp. Taylor |
 Ronan O'CaseyStefan Gordoni | Stefan Gordoni |
| LLaunce MaraschalJ.D. Everleigh | J.D. Everleigh |
 Colin TapleyLord Valchrist | Lord Valchrist |
 Alan GiffordHenry Warburg | Henry Warburg |
 Grace ArnoldLady Hawksley | Lady Hawksley |
 John ColicosMustachioed Henchman (as John Collicos) | Mustachioed Henchman (as John Collicos) |
| MMayuraYasmina | Yasmina |
| JJohn WatsonDetective Sgt. Grant | Detective Sgt. Grant |
| RReggie MorrisCleanshaven Henchman (as Reg Morris) | Cleanshaven Henchman (as Reg Morris) |
| DDerrick WhittinghamPrint Shop Manager | Print Shop Manager |
| CCharles HammondNot listed | Not listed |