Lord Peter discovers that the mysterious murdered man spent time in France and travels there to speak to his wife, and with the Vicar's help later later cracks a cipher.
| Name | Type | Role | |
|---|---|---|---|
| Dorothy L. Sayers | Writer | ||
| Anthony Steven | Writer | ||
| Kenneth Colley | Guest Star | ||
| Kate Beswick | Guest Star | ||
| Ginette McDonald | Guest Star | ||
| India Waters | Guest Star | ||
| Raymond Menmuir | Director |