EPISODE: The Sensorites Part 4: A Race Against Death
OVERALL EPISODE NUMBER: 034
STORY NUMBER: 007
TRANSMITTED: 18 July 1964
WRITER: Peter R. Newman
DIRECTOR: Mervyn Pinfield
SCRIPT EDITOR: David Whitaker
PRODUCER: Verity Lambert
FORMAT: VHS: Doctor Who - The First Doctor (The Sensorites , The Time Meddler & The Gunfighters)
Since Ian collapsed and was pronounced to be dying at the end of the last episode the title is appropriate!
The Doctor discovers that what Ian has isn't contagious and deduces it's the water Ian drank that the rest of them and the elders didn't. The Doctor thinks that it's more a poison than a disease and wants everyone to drink the water that the Elders alone drink. They get Ian to drink water & salt. The Doctor wants the Tardis lock back to get at his scientific instruments to cure Ian, but the Second Elder does not trust them. The Second Elder works to repair John's mind, but the Administrator argues with him. Second Elder goes to speak again with the First Elder and John accuses him of being evil. The female crew member, Carol, mistakes the Administrator for a scientist giving him the idea that he could pose as another Sensorite. The Sensorites won't allow the Doctor access to the TARDIS but let him use their lab. The Administrator confers with a colleague, they will lure the second Elder into a trap. The Doctor deduces which poison is in the water. Samples are gathered from all over the Sensesphere and the Doctor traces which area the poison is found. The Second Elder is held captive by the Administrator who poses as the Second Elder in order to disrupt the Doctor's activities. John is a little more lucid and tells the Doctor that there are enemies making plots. The Administrator seizes the antidote from the scientist: he believes Ian is pretending and will not die without it. The Doctor & The Scientist visit the aqueduct where they think the poisoned liquid is sourced from: The scientist is scared to enter both because of the dark and a belief there are monsters within. Susan finds some more of the antidote for Ian, who wants to go and find the Doctor. The First Elder telepathically contacts the Second telling him what has occurred. Unable to reply and in the clutches of the Administrator he is forced to tell the Administrator where they have gone. The Doctor finds the source of the poison, some deadly Nightshade just as he hears a monster bellowing.....
Barbara is missing from this episode or the next: she's on holiday.
The story picks up a bit this episode. The Sensorites being near identical is exploited by the plot and there's some menace from the Administrator's machinations.
The Sensorites is available on the BBC section of YouTube. You can find Episode 4 here.