The Mutants is the fourth serial of the ninth season of the British science fiction television series Doctor Who, which was first broadcast in six weekly parts on BBC1 from 8 April to 13 May 1972.
The militaristic and bigoted Marshal and other human soldiers, known as Overlords, rule it and the disunionised tribal Solonian people from Skybase One, an orbiting space station.
The Marshal opposes the decolonisation plans outlined by an Earth Administrator, and is obsessed with eradicating the arthropod-like mutants or "Mutts" developing on the planet.
The Third Doctor and Jo arrive on Skybase, the Time Lords having transported the TARDIS there, with a pod which will only open for an intended recipient, which seems to be Ky, another Solonian framed for the Administrator's murder.
The Doctor learns that the Marshal and his chief scientist Jaeger plan to terraform Solos, to make the planet habitable for humans, but not for indigenous life.
The Marshal later knowingly fumigates the caves with the Doctor, Jo, Ky, Stubbs, and Cotton still inside, but an outcast human scientist, Sondergaard, a Solonian anthropology expert, saves the group.
The Marshal later sentences summary execution on the remaining four, but are saved by Jaeger's timely revelation of the terraform attempt failing and instead poisoning Solos' environment.
To force the Doctor to rapidly decontaminate the planet with Skybase's technology before the Investigator's arrival, the Marshal imprisons Jo and the rest in a soon-to-be-radioactive thaesium refueling bay.
Escaping from the guards, the Doctor quickly studies the crystal in the Skybase laboratory, confirming that it focuses and converts thaesium radiation from the deposits deep in the caves, beneficially accelerating the mutation process.
The Marshal, now unbalanced from thoughts of ruling grandeur, forces Sondergaard (to whom the Doctor secretly gives the crystal), Jo, Cotton, and Ky back into the refueling bay.
There, Sondergaard gives a severely weakened Ky the crystal, who then absorbs all of the thaesium fuel and rapidly mutates, emerging as a radiant angel-like super-being and saving the prisoners.
The way the Marshal tries to keep the imperial project going in defiance of his own empire's wish to give up Solos in order to colonise it with millions of settlers from Earth was based on Rhodesia.
[3] The opening shot of the story features a bedraggled, hermit-like bearded figure (Sidney Johnson) shambling out of the mist towards the camera.
Both fans and Jon Pertwee alike have compared the scene to the "It's" man at the start of most episodes of Monty Python's Flying Circus.
[6] DVD Talk's John Sinnott gave the story two and a half out of five stars, calling it "terribly average" but "a solid adventure ... worth watching".
[14] IGN reviewer Arnold T. Blumburg gave the story a score of 7 out of 10, writing that there was more to be appreciated as an adult to see "its role as a hard-edged indictment of the culture in which it was created".
[15] Ian Berriman of SFX gave The Mutants three out of five stars, noting its ambition to tackle social issues but concluded that the execution was "bungled".
[7] Grady and Hemstron concluded that it not been for the colonialism the Solonians would have completed their life cycle without incident and that: "The episode is a fair warning that, no matter how well intended, interference with indigenous cultures can have dangerous and far-reaching consequences".