The Second Doctor and Jamie McCrimmon land the TARDIS on board Space Station Camera, where they talk to Dastari, the Head of Projects.
Dastari reveals his plan to dissect the Second Doctor's cell structure to isolate his symbiotic nuclei and give them to Chessene, an Androgum technologically augmented to genius levels.
[3] Hurndall's death in April 1984 saw the brief revised to feature the Second Doctor and Jamie,[4] but the setting had to be changed to Spain instead when the expected funding for location filming in the United States fell through.
Veteran actress Aimee Delamain appears in a cameo role as the ill-fated hacienda owner the Doña Arana.
[7] Patrick Mulkern of Radio Times awarded the serial two stars out of five, stating: "The Two Doctors wasn't dire, but the actors and audience deserved better.
"[9] Television historian Marcus Harmes says of it "Besides the inherent joy of having Troughton and Hines back, the location filming around the hacienda and up and down the alleys in Seville is evocative, and the guest cast is brilliant".
[10] The novelisation of this serial, by Robert Holmes, was published in hardback and paperback in August 1985 as the 100th Doctor Who release by Target Books.
The DVD contains a full-length commentary provided by director Peter Moffatt and actors Colin Baker, Nicola Bryant, Frazer Hines, and Jacqueline Pearce.
Following the sexual abuse accusations regarding Jimmy Savile, the DVD was withdrawn from sale but has since been rereleased with the offending sketch removed.
An extended cut of Part One was included as an extra on the set with a runtime of 47:33, running 3 minutes and 11 seconds longer than the original broadcast episode.