The Doctor has vanished from the Inferno project… or has he? He finds himself in the same place, but everyone has changed… and the drilling is closer to its deadly conclusion.
| Name | Type | Role | |
|---|---|---|---|
| Don Houghton | Writer | ||
| Nicholas Courtney | Guest Star | ||
| John Levene | Guest Star | ||
| Olaf Pooley | Guest Star | ||
| Derek Ware | Guest Star | ||
| Christopher Benjamin | Guest Star | ||
| David Simeon | Guest Star | ||
| Derek Newark | Guest Star | ||
| Ian Fairbairn | Guest Star | ||
| Sheila Dunne | Guest Star | ||
| Douglas Camfield | Director | ||
| Barry Letts | Director |