Bird lover Mrs. Wentworth Howe left her estate in trust, stipulating in her will that the money would not be distributed among any relatives as long as a bird remained alive in the aviary at the Howe mansion. When one of the birds is shot dead, estate trust attorney Laverick hires Jeff to investigate. When Jeff shows up at the mansion, the list of possible suspects grows shorter and shorter as the relatives are murdered one by one.
| Name | Type | Role | |
|---|---|---|---|
| Tony Williamson | Writer | ||
| Roy Ward Baker | Director | ||
| Maurice Hedley | Actor | Colonel Chalmers | |
| Susan Broderick | Actor | Carol | |
| Cyril Luckham | Actor | Laverick | |
| Tenniel Evans | Actor | James Howe | |
| Leslie Schofield | Actor | Peter | |
| Jane Merrow | Actor | Sandra Joyce | |
| Michael Goldie | Actor | Gimbal | |
| Mike Pratt | Actor | Jeff Randall | |
| Gabrielle Brune | Actor | Mrs. Howe | |
| David Webb | Actor | Police Sergeant | |
| Kenneth Cope | Actor | Marty Hopkirk | |
| David Lodge | Actor | Beeches | |
| Philip Lennard | Actor | Johns | |
| Annette Andre | Actor | Jean Hopkirk |