The Krotons is the fourth serial of the sixth season of the British science fiction television series Doctor Who, which was first broadcast in four weekly parts from 28 December 1968 to 18 January 1969.
On an unnamed planet, a race called the Gonds are subject to the mysterious Krotons, unseen beings to whom they provide their brightest intelligences as "companions".
The Second Doctor, Jamie and Zoe arrived in time to witness the death of Abu, one of the two chosen companions, who was vaporised by smoke sprayed from nozzles on either side of the doorway from which he emerged, and intervened to save Vana, the other selected for this fate, using her survival as a means to convince Selris and the Gonds of the malign influence of the Krotons on their society.
The newly created Krotons capture Jamie, but are really seeking the Doctor and Zoe, the "High Brains", who have now left the Dynatrope.
Eelek and Axus, two councillors previously loyal to the Krotons, begin to rally for all-out war with them and seize the initiative in Gond society.
Eelek has Selris arrested and reasserts control by negotiating with the Krotons that they will leave the planet if provided with the two "High Brains" who can help them power and pilot their ship.
The actor James Cairncross, who plays Beta, previously appeared as Lemaitre in The Reign of Terror with William Hartnell's First Doctor.
[1] Patrick Mulkern of the Radio Times gave the serial a mixed review, acknowledging that "The episodes are packed with incident, the slate-dark quarry filming is fluid and moody, and there are decent performances."
"[9] The serial was positively received by James Peaty of Den of Geek who noted that whilst the story was a fairly standard one it benefitted from the dramatic intensity and sharp dialogue crafted by writer Robert Holmes.
Although he considered the Krotons to be a "workaday adventure" Peaty said that "there are still many things to enjoy within its relatively brisk 90-minute running time.
The "special sounds" from this serial by Brian Hodgson at the BBC Radiophonic Workshop were released on CD, Digital Download on 13 May 2013 with a limited run of 10" vinyl 24 May 2013.