The last story of Season 4, 'The Evil of the Daleks' was originally intended to be the last ever Dalek story. It was also the story which introduced Victoria Waterfield as the Doctor's twelfth travelling companion. Only episode 2 remains of the original story, and the surviving episode can be seen on the BBC's "Daleks - Early Years"' video release.

The story starts at Gatwick Airport, south of London, in 1966. Ben and Polly have just left the Doctor after the previous adventure ('The Faceless Ones'), and as the Doctor and Jamie prepare to leave, they notice the TARDIS, which they had left by an airport hangar, is being carried away on the back of a lorry! Unable to catch the lorry, they turn their attention to the hangar from which the vehicle emerged...

The story was repeated a year after its original broadcast, and uniquely, the repeat was written into the programme's storyline. At the end of Zoe Herriot's debut story, 'The Wheel in Space', the Doctor tries to warn her of the dangers she will face on joining the TARDIS crew. He produces a telepathic projector from behind a roundel in the Control Room, and uses it to project memories of a previous adventure onto the TARDIS scanner. The adventure chosen is his previous encounter with the Daleks.

The introductory scene for the repeat has been transcribed, and is included with the script for episode 1.