An amateur detective investigates a string of acid bath murders while on holiday.
| Actor | Role |
|---|---|
 John LaurieMr Potter | Mr Potter |
 Hector RossInspector Greenway | Inspector Greenway |
| MMolly RaynorNot listed | Not listed |
| CCatherine CampbellNot listed | Not listed |
 Jack StewartNot listed | Not listed |
 Charles Lloyd PackHotel Manager | Hotel Manager |
| DDerek SidneyNot listed | Not listed |
| PPeter BathurstColonel | Colonel |
| VVernon GibbNot listed | Not listed |