Terminus

On the orders of the Black Guardian Turlough sabotages the console of the TARDIS. Fortunately he doesn't fully succeed. As the alarms sound the Doctor rushes in, and Turlough acts innocent, although Tegan is not so sure. The Doctor finds that the Time Rotor is jamming, and as an emergency precaution the TARDIS locks onto the side of a leper ship.

At the same time a raiding party raids the ship believing that there is wealth aboard. When the leader realises he runs off, leaving the party behind. Everyone is trapped as the ship is sterilised. As the lepers leave the ship, Nyssa is touched and infected, and the guards treat her no differently.

The process of curing the lazar disease involves a dose of radiation, but when the Doctor investigates he finds that the ship's pilot was killed centuries ago, and that the computer was going to jettison the ship's fuel, which would cause Event Two: The destruction of the Universe.

Enlisting the help of a creature known as the Garm the Doctor manages to prevent the fuel dump, and disconnect the computer controls. While the Doctor, Turlough and Tegan return to the TARDIS, Nyssa remains behind to show how to synthesise a drug that keeps the guards going, and how to process the lazar's properly.

• The Black Guardian: Valentine Dyall;
• Lari: Liza Goddard;
• Olvir: Dominic Guard;
• Tannoy Voice: Martin Mulcaster (1-2,4);
• Inga: Rachel Weaver (1,3);
• Eirak: Martin Potter (2-4);
• Valguard: Andrew Burt (2-4);
• Sigurd: Tim Munro (2-4);
• Bor: Peter Benson (2-4);
• The Garm: R. J.Bell (2-4);


• UNCREDITED CAST:
• Lazars: Fiona Alexander, Olwyn Atkinson, David Ballard, Rosemary Banks, Barbara Bermel, Chris Bradshaw, David Bulbeck, Johnny Clayton, Amir Coleman, Susan Dady, Christine Eatwell, Jill Goldstone, Martin Grant, Allen Hall, Janice Hollin, Mark Howard, Graham Jarvis, Anita Jayne, Nick Joseph, Debbi Lloyd, Ray Martin, Mykell Mills, Lee Montgomery, Pat Pelton, Annette Peters, Barbara Russell, Lionel Sansby, Rebecca Semark, Norman Warren;