|Edition: || UK (VHS)|
|Released: ||November 1992|
|Publisher: ||BBC Video|
|Format: ||1 x VHS PAL|
Earth 1983. The mysterious Black Guardian hovers over the shoulder of English public schoolboy, Turlough, determined to enlist his aid in his deadly scheme — the assassination of the Doctor. Meanwhile the Tardis is trapped inside a huge space ship in perpetual orbit, a permanent resting place for the miserable Mawdryn and his 8 fellow scientists, all condemned to a state of perpetual regeneration. Only the Doctor's life force can free them, but at a deadly cost — the price of his powers of regeneration.
With Nyssa and Tegan stranded in the time zone of 1977, and the Black Guardian closing in, the Doctor must face a terrible dilemma...
Originally transmitted 1 - 9 February 1983, this four part adventure is the first in the Black Guardian trilogy and sees the return of a familiar face — Brigadier Lethbridge-Stewart (Nicholas Courtney) — and the introduction of a new one — Turlough, (Mark Strickson) who went on to become the Doctor's new assistant.