The Doctor and Lucie investigate a vast biodome complex where an environmental crusade has taken a dangerous turn, with the Krynoid threatening to become humanity’s extinction event.
| Name | Type | Role | |
|---|---|---|---|
| Nigel Planer | Guest Star | Alex Marlowe | |
| Lysette Anthony | Guest Star | Hazel Bright | |
| Stuart Crossman | Guest Star | Stefan Radek | |
| Barnaby Edwards | Guest Star | Newsreader |