The Tyrants of Logic (audio story)

 was the second and final story in the audio anthology The Third Doctor Adventures: Volume Four, produced by Big Finish Productions. It was written by Marc Platt and featured Tim Treloar as the Third Doctor and Katy Manning as Jo Grant.

Publisher's summary
The Doctor and Jo land on Port Anvil — a bleak, abandoned mining colony on the remote planet Burnt Salt. A huge armoured crate has recently arrived in the almost derelict Spacehub. No-one knows who it's for. No-one knows what it contains.

Strange creatures lurk around the outskirts, and a rag-tag population of misfits inhabit what is left of the town: a saloon bar owner, a literal one-man band and a hunter of very unusual prey. If they want to survive the night, they're going to have to work together.

Because the Cybermen want the contents of the crate. And they will stop at nothing to get hold of it.

Part one
A mysterious freighter arrives on the planet of Burnt Salt in Port Anvil and when investigated by Gusta and Chad Caramel, they find the crew dead and go to find help. In the meantime, the Doctor and Jo arrive on the planet and investigate the same ship when they see it, while being watched from afar by a mysterious stranger named Hollisen Grier. When the bodies inside come alive and attack, Grier destroys them and after finding the Doctor and Jo orders them to go back to Gusta's bar. Gusta explains what happened to Burnt Salt and the invasion due to the Cyber War and how she was nearly converted, escaped and was abandoned like many others in the after-math and the Doctor sympathises with her. The Doctor has a chat with Grier and learns he is a Cyber-hunter. Just then the power goes out and Gusta goes to investigate the nearby hanger, secretly followed by Jo. Grier gets a signal of an incoming ship and he and the Doctor go to its expected landing spot... the same place Jo and Gusta have gone to investigate. They arrive and find a still-sealed capsule along with Gusta accusing Jo of being a saboteur and demanding to know where the capsule came from when suddenly a ship lands and the Cybermen emerge...

Part two
They stop the Cybermen but only too late as a signal has been activated alerting the other Cybermen the location. The Doctor orders Jo and Gusta to get protective suits from the bar while he and Grier build an energy net, having discovered that there is a Cyber-Leveller present. Jo and Gusta spot Cybermats and return with the suits to alert the Doctor, which they all put on. Soon Cyber-smoke is released. Once it clears they remove their helmets and Jo and the Doctor have a chat, after which he talks to Grier. Gusta contacts Professor Marian Schaeffer and informs her of the capsule but when she asks what it is Schaeffer dodges the question and ends the call. She and Jo suddenly find Chad coming down with a fever and is getting sicker at every minute. The Doctor and Grier, meanwhile, hear something trying to get out of the capsule and Grier reveals he was tracking the illegal sale of this pod and is trying to find out who did it, what the pod is and what it will be used for. Chad is compulsively compelled to go outside and Jo follows him, where they are eventually found a by a group of Cybermen but manage to escape and make it back to the hanger with the Doctor and Grier. The Cybermen have followed them (unknown to them through Chad who, having accidentally inhaled some Cyber-smoke earlier is slowly becoming a Cyberman) and attempt to bargain for the release of the Leveller but are overcome by the energy net. However, the Cyber-Leveller is awakened and releases a Cybermat into the Doctor's suit where it tries to choke him...

Part three
The Doctor is saved by Grier and Jo, however, Gusta, in a mining vehicle, crashes through the wall and steals the Leveller, leaving them in the aftermath. They find Chad and find out where Gusta is headed and watch him die, unable to cope with the conversion process, leaving Jo in tears. They head to the Bernard Schaeffer project based on a scan the Doctor does from Chad's advice, while Grier explains Marian Schaeffer's history.

Gusta arrives and drops off the pod for Schaeffer claiming she just wants to be rid of it and asks in return for a new eye and parts for Chad, seeing as she's done this favour for Schaeffer. Schaeffer then heads into the gardens and finds Skippa has returned (she had been found and was chatting with Jo earlier near the hanger), who sees Schaeffer as her mother but begs her to get rid of the capsule, convinced something bad is inside it. Schaeffer ignores her and assures her it's alright. As the Doctor, Jo and Grier approach the Bernard Schaeffer Sanctuary, the Doctor begins to act strange. Meanwhile, Schaeffer "examines" Gusta but reveals she was using her as a "test subject", and dosing her with a small sample of Cyber-smoke, terrifying Gusta. Just then Schaeffer is contacted by Skippa who informs her that a convoy of Cybermen are arriving.

The Doctor finds himself succumbing to the Cybersmoke and preparing for conversion, losing control of his mind. Grier fears it is too late and prepares to shoot him before he fully converts while Jo tries to save him when a Cyber-ship arrives but carrying Skippa and her sisters and tells Jo to get the Doctor aboard so they can bring him to Schaeffer who may be able to help the Doctor. They arrive and are greeted by Professor Schaeffer, who offers the Doctor and Jo a room for him to sleep in while she prepares to operate and secretly angry with but thanks Skippa for bringing her new test subjects. Grier confronts her about the Leveller and she reveals her deception, believing she can control them but Grier informs her she's in for a nasty shock, and already the lights begin to flicker, as the Cyber-leveller she has brought inside is attempting to take over the controls.

Jo, meanwhile, cries over the Doctor's state and Skippa asks her about it but suddenly the power begins to go out. Jo finds Grier and Schaeffer and asks what is happening but they are contacted by the Cybermen who demand they relinquish control of the Cyber-Leveller...

Part four
Schaeffer locks Jo and Grier in the control room amidst their protests and goes to confront the Cybermen, believing she can reason with them. The Doctor, in the meantime, manages to hold off the conversion and finds Jo and Grier, after which they make a plan where Grier will go to get some laser lances from Gusta's vehicle to fight the Cybermen with while Jo and the Doctor go searching for Grier. Schaeffer continues to operate on Gusta while Grier tries to convince Skippa that her mother needs to be stopped and to fight with them while the Doctor and Jo find and confront Schaeffer. Grier and Skippa are captured while Schaeffer reveals to an angry Doctor and Jo, after they have been found by Gusta who reveals Schaeffer's deception and injecting her with Cyber-smoke, why she is so insistent on talking with the Cybermen: her husband Bernard is a partially-converted Cyberman whom she found after the war. She explains to the Doctor she has been researching an antidote to the Cyber-smoke and was going to use it on the Cybermen which was why she attempted to lure them to Burnt Salt almost as an act of retribution for her husband's present state.

Meanwhile the Cybermen threaten Skippa with killing one of her sisters unless she reveals the Cyber-Leveller's location and despite Grier's protests to resist she tells them anyway and they proceed, keeping the two as hostages in case it is a trap. The Doctor and Jo confront the Cyber-Leveller and the Doctor manages to stall it while probing its mind through the link they have to find its weakness and find a way to counter-act the Cyber-smoke Cyber-particles, which he writes down and gives to Jo to bring to Schaeffer. She attempts to escape but the Cyber-Leveller sends the newly-enslaved Doctor after her while the Cybermen find the Cyber-Leveller and extract the code from Skippa's mind to shut off the barrier keeping the Cyber-Leveller caged. Jo gives the Doctor's discovery to Schaeffer who programs the computer to execute the instructions while Jo attempts to reverse the Doctor's processing. The Cyber-Leveller, finally free, finds Schaeffer and reveals that it had no intention of listening to her but Schaeffer counters them explaining that the Doctor's correction to the anti-Cyber-smoke is finally completed and releases it while Grier arrives and uses a sonic grenade, destroying the Cybermen and curing the Doctor but he passes out.

The Doctor wakes up and Jo explains everything while the Doctor meets a partially-cured Bernard Schaeffer who thanks him for his help and, although still partially converted, still has his humanity intact.

Cast

 * The Doctor - Tim Treloar
 * Jo Grant - Katy Manning
 * Gusta Pardo - Linda Marlowe
 * Professor Marian Schaeffer - Carolyn Pickles
 * Hollisen Grier - Ronan Summers
 * Chad Caramel - Jeff Rawle
 * Skippa - Deli Segal
 * The Cybermen - Nicholas Briggs

Uncredited Cast

 * Bernard Schaeffer - Nicholas Briggs

Individuals

 * Hollisen Grier is a Cyber-hunter.
 * The Doctor is exposed to Cyber-smoke.
 * Bernard Schaeffer used to present 3D wildlife documentaries, visiting hundreds of planets to study the wildlife. He was a naturalist and a zoologist.
 * Bernard Schaeffer supposedly died 10 years ago. He was actually Cyber-converted 19 years ago.
 * Prof. Marian Schaeffer trained as a surgeon, but now works as a scientist at the Bernard Schaeffer Project.
 * Skippa is one of her experiments.
 * She gave Gusta a new eye nine years ago.
 * The project complex contains a forest biome, and a Dead Zone, where Marian places the Cyber-leveller.

Buildings

 * Gusta runs a saloon called Gusta's.

Items

 * The Doctor gives Jo his TARDIS key, fearing the worst.

Music

 * Jo asks the music player Chad if he does requests such as Jimi Hendrix or the Beatles.
 * Chad Caramel the maestro had twelve different instruments grafted into him and toured in places such as Phantom's Moon and the Palladium Saucer before getting stuck on Burning Salt.

Institutions

 * BCR stands for the Bureau for Cyber Retribution. Grier works for them.

Planets

 * Burnt Salt used to have 4 moons but one of them was destroyed by a conflict between factions of the Cyber-resistance movements.

Equipment

 * Grier uses a sonic grenade.

Alien Species

 * Jo meets Skippa, who is a Lamura. Jo describes the Lamuri to the Doctor as similar to dancing lemurs with large green eyes that always seem like they just met you.

Continuity

 * Lucanol (TV: The Robots of Death) and duralinium (TV: The Monster of Peladon, Colony in Space) were once mined in Port Anvil.
 * The Doctor refers to his exile on Earth. (TV: Spearhead from Space – The Three Doctors)
 * Grier has a glittergun to fight against Cybermats. The Doctor claims he's never seen such a device before. He would later see one in action on station Nerva Beacon while attempting to stop the Cybermen destroying Voga. (TV: Revenge of the Cybermen)
 * The Cybermen recognise the Doctor but note that his appearance has changed again. The Doctor is a Time Lord and regenerates. (TV: The Tenth Planet, The War Games et al.) He also encountered the Cybermen on several occasions such as on Mondas and in the London sewers among other incidents. (TV: The Tenth Planet, The Invasion et al.)
 * The Doctor stops to admire the landscapes of Burnt Salt and reminds himself of recently becoming free after his exile on Earth and how he missed exploring the wonders of the universe. He was initially exiled to Earth by the Time Lords but was later freed after performing a service for them and given back control of the TARDIS. (TV: The War Games, Spearhead from Space, The Three Doctors)
 * The Doctor compares the tropical atmosphere of the Bernard Schaeffer project to that of Shangri-La. He would later visit the holiday camp in his seventh incarnation along with Mel. (TV: Delta and the Bannermen)