Doctor Who/Recap/S9 E4 The Mutants

"Grey cities linked by grey highways across a grey desert. Slag, ash and clinker - the fruits of technology."

- The Doctor isn't a fan of 30th century Earth

The Doctor is off on another mission for the Time Lords (who presumably figure that giving him busywork will keep him out of trouble) - he has a sealed message to deliver to recipients unknown aboard a space station orbiting the planet Solos in the 30th century. Solos is about to gain independence from Earth's Empire, but the Marshal in command is determined to prevent this and is working with scientist Jaeger to convert Solos's atmosphere into an Earth-like one which will kill the Solonians.

The Earth administrator is murdered on the Marshal's orders and Ky, a young Solonian leader, is framed and flees to the planet, taking Jo with him. The Doctor follows, and his message pod opens for Ky, evidently the intended recipient. The contents of the pod turn out to be some ancient carved stone tablets.

Exploring the Thaesium mine in which they find themselves, the Doctor meets a human scientist called Sondergaard, who is searching for a cure for the mutating disease affecting the Solonians. The tablets turn out to be information about the history of the Solonians - apparently the mutations are part of a natural cycle and not a disease at all, and the radiation from the mined Thaesium is part of the cycle.

The Doctor takes a crystal from the mine and returns to the space station to use the laboratory, but is captured by the Marshal along with Jo and Ky and forced to complete the atmosphere converter. Sondergaard gives the crystal to Ky, who mutates first into a hideous creature, then an ethereal angelic being (apparently the ultimate mutation of the Solonians). The Doctor once again sabotages the machine, killing Jaeger, and Ky evaporates the Marshal.

Tropes

 * Arcadia
 * Beauty Equals Goodness
 * Black Dude Dies First - Averted, as it is who gets killed.
 * Conspicuously Public Assassination
 * Continuous Decompression
 * Dying as Yourself - Varan's and his followers' plan, when they think that mutation is a bad thing.
 * Everyone Calls Him "Barkeep" - they really go for it in this story, with the Marshall, the Administrator and the Investigator. It's not just the humans - Varan's son doesn't get a name either (although he is given one - Vorn - in the novelisation).
 * Evolutionary Levels - with a twist on the usual human-centric scale. Here Human Aliens < Insectoid Aliens < Energy Beings
 * Fantastic Racism
 * Fantastic Slurs: "mutt" (originally intended to be "munt", a real ethnic slur used by English-speaking people in southern Africa against black Africans)
 * Fat Bastard: the Marshal
 * Going Native - Sondergaard
 * Humans Are Bastards
 * I Love Nuclear Power - Averted
 * Made a Slave
 * Motive Rant - a short but effective one, when the Doctor gets the Marshall to express himself about the mutants in front of the Investigator.
 * Mutants - Naturally!
 * Name's the Same - Cotton is played by Rick James, but not that Rick James.
 * Noble Savage - Ky, in particular
 * Occupiers Out of Our Country!
 * One-Gender Race - no female Solonians are visible at any point. Then again, this is one of the few Doctor Who stories with no female guest cast members at all.
 * Physical God - The final phase of the Solonians' metamorphosis.
 * Planetville
 * The Quisling - Varan, to start with
 * Revenge
 * Reverse the Polarity - Particle Reversal can do anything
 * Terraform - the bad guys' plan.
 * Thicker Than Water
 * Third Person Person: Varan. Seemingly a personal affectation, as the other Solonians don't do it.
 * Those Two Guys/ Those Two Bad Guys - Stubbs and Cotton, the two security guards who chip in with observations throughout the story.
 * What Measure Is a Non-Human? - lampshaded and attacked throughout