Young Anthony Pendrell plays the precocious son of Scotland Yard inspector Norman Shelley. Pendrell's efforts to emulate his father usually results in nothing but irritation for his elders. But when a boarding house becomes the headquarters for a criminal gang, it is Pendrell who cracks the case.
| Actor | Role |
|---|---|
 Zena MarshallChristine Stevens | Christine Stevens |
 Sydney TaflerRicky Martin | Ricky Martin |
| AAnthony PendrellRoger Morley | Roger Morley |
 Russell NapierStevens | Stevens |
 Norman ShelleySuperintendent Morley | Superintendent Morley |
 John Le MesurierLefty Jones | Lefty Jones |
| TTony DoonanCharley (as Anthony Doonan) | Charley (as Anthony Doonan) |
 Barbara ShawClare Raven | Clare Raven |