11 September 1965
Stephanie Bidmead (Maaga), Marina Martin (Drahvin One), Susanna Caroll (Drahvin Two), Lyn Ashley (Drahvin Three), Jimmy Kaye , William Shearer, Angelo Muscat, Pepi PoupÃ©e [3-4], Tommy Reynolds  (Chumblies), Robert Cartland (Rill Voices) [3-4], Barry Jackson (Garvey) *
|Written by||William Emms|
|Directed by||Derek Martinus|
|Produced by||Verity Lambert|
Following a skirmish in deep space, two alien spacecraft have crashlanded on a barren planet. The Drahvins are a race of beautiful females, led by the imperious Maaga. The Rills are hideous tusked monstrosities, accompanied by their robotic servants, the Chumblies.
When The Doctor arrives, he discovers that the planet will explode in two days’ time. The Drahvins desperately ask for his help in escaping the planet and the hostile Rills.
But things are not always as they seem.
- The working title for this story was The Chumblies. (the First Doctor Handbook)
- The continuity from this story runs through until The Daleks’ Master Plan. at the end of episode 4, Vicki complains of a sprained ankle. As she contemplates the planet Kembel on the scanner, there is a short scene with Garvey as he begins his transformation into a Varga plant. Garvey as a Varga later threatens Cory and Lowrey in Mission to the Unknown. When we next see the TARDIS at the beginning of The Myth Makers, Vicki still has a hurt ankle. Finally, after taking off at the conclusion of the Myth Makers, The Doctor discovers Cory’s tape on Kembel during the first episode of The Daleks’ Master Plan. Mission thus presents an unusual example of the story-to-story narrative flow that was commonplace in the Hartnell era.
- * All four episodes of this story were thought lost, with only very limited material held in the BBC archive. Episode 3 was recovered in July 2011,  and its return was announced on 11 December 2011. 
- Six minutes of footage exists from”Four Hundred Dawns”. The surviving clips come from a number of sources including a Lively Arts documentary WhoIsDoctorWho.
- Ian Levine claimed that The Doctor Who Appreciation Society obtained legal permission to screen this serial at a convention privately in 1978, only to find that the BBC had junked the episodes about three weeks earlier. Later research showed this to be mistaken. The DWAS never had any agreement to show the serial and BBC Enterprises appear to have junked at least one of the episodes by the end of 1976.
- The only surviving publicity still featuring a Rill.
- The soundtrack for the serial is intact and has been released commercially by BBC Audio with linking narration provided by Peter Purves.
- The appearance of the Rills and the characters’ reaction to it is similar to, if not based upon, Journey Into Space: Operation Luna.
- The Drahivns’ use of clones was likely inspired by the novel Brave New World.
- The BBC partly own the rights to the Drahvins as they were jointly credits to William Emms and Verity Lambert. Emms created the (originally male) Drahvins, whilst Lambert made them female.
- The Bonzo Dog Doo Dah Band’s 1968 song”Beautiful Zelda” included lyrics about”Beautiful Zelda from Galaxy Four”, perhaps inspired by Galaxy 4.
- The stock music used for the soundtrack was performed by an experimental group called Les Structures Sonorés. They performed their music on glass tubes. Some of the same music was used in The Web Planet.
- The most recent discovered episode called Air Lock – was released on the Aztecs Special Edition DVD