Drake's latest case is to unravel a security leak. The suspect is Ruth Mitchell, an interpreter; but as Drake later discovers, the girl has been used without her knowledge.
| Name | Type | Role | |
|---|---|---|---|
| Ralph Smart | Writer | ||
| Robert Stewart | Writer | ||
| Brian Rawlinson | Guest Star | ||
| Moira Redmond | Guest Star | ||
| Charles Vance | Guest Star | ||
| Duncan Lamont | Guest Star | ||
| Tom Gill | Guest Star | ||
| Pauline Letts | Guest Star | ||
| Stanley Van Beers | Guest Star | ||
| Henry Vidon | Guest Star | ||
| Paul Maxwell | Guest Star | ||
| Anthony Bushell | Director |