'The Visitation' (4 Parts) Story Code '5X' by Eric Saward

The Doctor attempts to return Tegan to Heathrow airport in 1981, but the TARDIS overshoots and lands in England in 1666, at the time of the Great Plague. The Doctor, Tegan, Adric and Nyssa meet Richard Mace, a travelling thespian, who tells them of a comet that he recently saw fall from the sky. The Doctor and his friends find power packs in a loft, encounter an android dressed as the Grim Reaper, and are attacked by villagers whose minds seem to be under the influence of control bracelets. The strange occurrences centre on the village grange, and when the time travellers attempt to break in to investigate, Adric and Tegan are captured by the Android, while the Doctor, Nyssa and Mace escape. Adric and Tegan meet an alien creature known as a Terileptil, one of three alien fugitives that escaped from Raaga, a prison planet, and whose space capsule subsequently crashed on Earth. Tegan is placed under the control of a bracelet, but Adric escapes. He makes his way back to the TARDIS, meeting up with the Doctor, Mace and Nyssa. But the android appears and captures the Time Lord, taking him back to the grange. Here, the Doctor offers to help the Terileptil leader, but the creature refuses, instead planning to unleash an army of plague carrying rats that will wipe out the population, leaving it free for them to inhabit. Leaving Tegan about to unleash plague-carrying rats that will attack the Doctor, the Terileptil departs for London. The Doctor manages to free Tegan from her conditioning, while, back at the TARDIS, Nyssa destroys the android with a sonic machine. The Doctor, Tegan, Nyssa, Adric and Mace journey in the TARDIS to London, where they find the Terileptils in their base at a bakery. A fight breaks out, and when a flaming torch ignites the bakery, a Terileptil gun explodes, killing the aliens in the conflagration. The Doctor and his friends throw the plague vials into the fire, which is now out of control. The travellers leave as the Great Fire of London begins...

Peter Davison (The Doctor), Matthew Waterhouse (Adric), Janet Fielding (Tegan), Sarah Sutton (Nyssa), Michael Robbins (Richard Mace), Peter Van Dissel (Android), John Savident (The Squire), Anthony Calf (Charles), John Baker (Ralph), Valerie Fyfer (Elizabeth), Richard Hampton (Villager), James Charlton (Miller), Michael Melia (Terileptil), Neil West (Poacher), Eric Dodson (Headman)

Produced by John Nathan-Turner
Directed by Peter Moffat

TX:
Part 1 - 15th February, 1982 @ 6.55pm - 7.20pm
Part 2 - 16th February, 1982 @ 7.05pm - 7.30pm
Part 3 - 22nd February, 1982 @ 6.55pm - 7.20pm
Part 4 - 23rd February, 1982 @ 7.05pm - 7.30pm

Notes:
*Featuring the Fifth Doctor, Adric, Nyssa and Tegan

*Working titles: 'Invasion of the Plague Men' and 'The Plague Rats'