The colonel Daniel Blimp, of the secret British service, travels to Bangkok to investigate the murder of the Brittish Ambassador happened during a holiday in his residence. Blimp receives the help of Keats, agent of the secret service. Both men discover that the man who shot against the Ambassador is blind, and it takes the black skin as a result of a strange phenomenon of mutation.
| Actor | Role |
|---|---|
 Howard VernonCoronel Daniel J. Blimp | Coronel Daniel J. Blimp |
| HHelena GarretMarion Wentworth | Marion Wentworth |
 José LlamasBill Sanders | Bill Sanders |
| TTrino TrivesTao | Tao |
| AAna EspejoMadame Rita | Madame Rita |
| CChristian BorckJonathan Keats | Jonathan Keats |
| RRafael CorésWelbeck | Welbeck |
| JJuan SolerByron | Byron |
| JJosé Miguel GarcíaAmoc mutant | Amoc mutant |
| ÓÓscar San JuanNot listed | Not listed |
 Jesús FrancoRose Hotel's recepcionist (uncredited) | Rose Hotel's recepcionist (uncredited) |
| JJuana de la MorenaDra. Carlson (uncredited) | Dra. Carlson (uncredited) |
| JJulia TeranNot listed | Not listed |