Scaroth is determined to go back 400 million years in time to prevent a mistake. But the Doctor must stop him – because the consequences would be disastrous.
| Name | Type | Role | |
|---|---|---|---|
| Douglas Adams | Writer | ||
| Graham Williams | Writer | ||
| John Cleese | Guest Star | ||
| Catherine Schell | Guest Star | ||
| Kevin Flood | Guest Star | ||
| Eleanor Bron | Guest Star | ||
| Michael Hayes | Director |