The Rani has returned with another malicious scientific scheme. Taking advantage of the post-regenerative trauma the recently regenerated and unstable Doctor is going through, she hopes to achieve control of an approaching asteroid composed entirely of strange matter. Can the Doctor figure out he is being used for the Rani's evil experiment, and what is behind the door the Rani won't allow him past?
| Actor | Role |
|---|---|
 Sylvester McCoyThe Doctor | The Doctor |
 Bonnie LangfordMel Bush | Mel Bush |
 Kate O'MaraThe Rani | The Rani |
| MMark GreenstreetIkona | Ikona |
 Wanda VenthamFaroon | Faroon |
 Donald PickeringBeyus | Beyus |
| KKaren CleggSarn | Sarn |
| RRichard GauntlettUrak | Urak |
| JJohn SegalLanisha | Lanisha |
 Peter TuddenhamSpecial Voices (voice) | Special Voices (voice) |
| JJacki WebbSpecial Voices (voice) | Special Voices (voice) |