While repairing the TARDIS, the Doctor finds it stopped in deep space. He knows it needs Zeiton-7 to realign the power systems, but the element is rare and can only be found on the planet Varos.
On Varos, a former prison planet, is a dystopian society where voting is mandatory, torture and execution are televised, and the governor can be killed by the public. The Galatron Mining Corporation Mentor Representative Sil (Nabil Sharan), a tiny aquatic creature with a nasty personality, is negotiating with the governor (Martin Jarvis) over the price of Zeiton-7 ore. Not knowing that his chief officer (Forbes Collins) is in league with Sil, the governor calls for a vote on whether they should hold out for a better price, but he loses the vote and thus may be subjected to Human Cell Disintegration Bombardment. He pleases the citizens by ordering the execution of Rebel Leader Jondar (Jason Connery). The TARDIS lands at the punishment dome.
The guard thinks the TARDIS is a hallucination brought on by the radiation being used to torture the Rebel Jondar. The Doctor incapacitates the guard and frees Jondar, but more guards appear, and the time-travellers flee with Jondar to his wife Areta (Geraldine Alexander). The Doctor is separated from the others, who are arrested. He enters a corridor that appears in his mind to be a desert, while the public watches on TV, and begins to die of thirst. Peri has been brought to the Control Centre with the governor, Sil, and others.
They question Peri as she watches the Doctor’s body being disposed of, but he has actually survived and is arrested by Varos’ Chief Scientist Quillam (Nicholas Chagrin). The governor decrees that the Doctor and Jondar will be hanged, and Peri and Areta experimented on. On the gallows, the Doctor offers his help in the Zeiton-7 matter. Sil quickly orders his guards to pull the lever to hang him. But it turns out it was all a trick to get information from the Doctor. The Doctor agrees to help on the condition that Peri and Areta are unharmed. Quillam refuses and the Doctor shoots the control panel, halting and reversing the mutations. The four escape, but Peri, in a stupor, is recaptured.
The Chief Officer and Sil move against the governor, hoping that losing the next vote will result in his being executed, while the Doctor, Jondar, and Areta head for the End Zone of the Dome. The vote starts and a radiation bombardment begins, but a guard stops the device, saving the governor and Peri. They meet up with the Doctor. Cannibals chase them, but they are attacked by plants. The fugitives head back to the Control Centre and Sil reveals his invasion force. However, Sil learns that a second Zeiton-7 deposit has been discovered and the company orders him to obtain the ore at any price. The Doctor and Peri take some Zeiton-7 and leave in the TARDIS. The governor abolishes the injustice, torture, and executions.
This was a pretty dark story for Doctor Who. Some of the comedic scenes were cut and what was left was dystopian, to say the least. During the hanging scene, the set collapsed beneath the actors, but Colin Baker’s and Jason Connery’s heads were not in the nooses at the time. Jason Connery is, of course, the handsome son of Sean Connery. Not too surprisingly, the violent content was controversial, particularly the acid bath execution and the weird-science torture of the women. The death of the guards in the acid bath was filmed in such a way that the Doctor appeared to some to have pushed them in, and then he made a flippant remark, the kind we expect from James Bond and Arnold Schwarzenegger, but seems rather shocking from the Doctor. Nicola Bryant was covered in feathers for her transformation into a bird-creature, but she was allergic and suffered for it.
John Hurt, Derek Jacobi, Julian Glover, Brian Blessed, David Warner, and Ian McKellen were considered for the governor, which is not to say the production had a hope in hell of getting any of them. Sil was played by Nabil Shaban, a brilliant actor with an undeveloped lower body who has played many villains and aliens. He was hired because Isaac Asimov mentioned that aquatic creatures seldom appeared in SF TV shows and movies. Patrick Stewart was considered for the Chief Officer. Two characters throughout the story—Arak and Etta (Stephan Yardley and Sheila Read)—have no contact with any of the other characters, but have been watching the tortures and murders on TV, voting on the governor, and complaining about the programming. Now that there will be no more cruelty and death to watch, they wonder what they are going to do with themselves.