While operating the controls on his TARDIS console, The Doctor accidentally transports his former companion Tegan Jovanka on board. Less than happy about her situation, she reluctantly agrees to help when the Doctor reveals that two Sontarans are on board with a powerful vitrox bomb with which they intend to blow up the ship.
| Actor | Role |
|---|---|
 Colin BakerThe Doctor | The Doctor |
 Janet FieldingTegan Jovanka | Tegan Jovanka |
| GGareth JenkinsHimself | Himself |
 Clinton GreynGroup Marshal Nathan | Group Marshal Nathan |
| TTim RaynhamSontaran Turner | Sontaran Turner |
 Jimmy SavileHimself | Himself |