The Doctor and Sarah answer a distress call and find themselves on Zeta Minor, the last planet of the known universe, where a Morestran expedition has gone missing.
| Name | Type | Role | |
|---|---|---|---|
| Louis Marks | Writer | ||
| Robert Holmes | Writer | ||
| Louis Mahoney | Guest Star | ||
| Terence Brook | Guest Star | ||
| Tony McEwan | Guest Star | ||
| Haydn Wood | Guest Star | ||
| David Maloney | Director |