Strange, rhymed advertisements in the newspaper unsettle three London gangsters - and rightly so, because soon the first of them are killed. The mysterious killer also catches a shady lawyer. Higgins and Lane find out that the key to the crimes is an unsolved diamond heist.
| Actor | Role |
|---|---|
 Gunter BergerInspektor Higgins | Inspektor Higgins |
 Mariella AhrensBarbara Lane | Barbara Lane |
 Eddi ArentSir John | Sir John |
| RRosalind BaffoeAnn Pattison | Ann Pattison |
 Udo SchenkWilliam Bolden | William Bolden |
 Julia RichterPeggy Lynch | Peggy Lynch |
 Helen VitaLady Upperworth | Lady Upperworth |
 Eva EbnerMiss Thinwhister | Miss Thinwhister |
| KKlaus LehmannStephen Scott | Stephen Scott |
 Peggy LukacRuth Bolden | Ruth Bolden |
 H.H. MüllerTom Averil | Tom Averil |
 Georg TryphonMr. Nelly | Mr. Nelly |
 Mogens von GadowRobert Frazer | Robert Frazer |
 Axel PrahlTaxi driver | Taxi driver |