The Doctor and Leela in the TARDIS

The TARDIS arrives in the far future on the planet Pluto where there are now six suns, a breathable atmosphere and a large thriving industrial community - the city of Megropolis One.

The Doctor and Leela soon discover that the people, such as the D-grades, are not so happy as the Company, that controls the planet and owns the false suns that have been created around Pluto to provide the ability for some of mankind to live, is using its economic stranglehold over mankind to extort ever growing taxes. The Company exploits the workers by working them to the bone, pays them a pittance and then taxes them on everything imaginable.

As soon as they arrive, on the roof of Megropolis One, The Doctor and Leela witness Cordo, a D-grade citizen, who is so overwhelmed by the size of his tax bill that he has decided to take his own life by jumping from the roof. But luckily the arrival of The Doctor and Leela saves him from his chosen fate. The Doctor and Leela learn from Cordo that each Megropolis is ruled by a taxation Gatherer, and the entire operation on the planet reports to a malevolent Usurian known as The Collector.

The Doctor and K9 Playing Chess

The Usurians are notorious for enslaving whole planets through business ventures and then fleecing the inhabitants through exorbitant taxes and other bureaucratic means. The Collector though is a particularly nasty, bald-headed, green-hued, wheelchair bound, money-grabbing individual, who has the population well and truly subjugated while the Company continues to make ever greater profits.

The Doctor learns that some of the citizens have rejected this social order and have chosen to live in the dark tunnels of the Undercity. The Doctor and Leela, along with Cordo, decide to venture underground so as to encounter the band of rebels. They discover that the renegades are a vicious bunch of thieves and drop-outs, led by the brutal Mandrel, who are out to smash the system.

Leela Exiting the TARDIS

However, when Leela is held hostage by the rebels, who threaten to kill her, The Doctor is forced to attempt to withdraw some money - a thousand Talmars - from a Consumbank booth using a stolen and forged Consumcard. To assist him The Doctor summons K9 from the TARDIS unaware that the Gatherer of Megropolis One, Gatherer Hade, has been alerted to the arrival of the TARDIS and uses an electronic tracker to follow K9 as the robotic dog searches for his master. K9 soon finds The Doctor and Cordo at the Consumbank booth. Gatherer Hade also sees them and suspects they must be arms dealers and so arranges for the booth to be filled with a gas. Overcome by the cloud of noxious gas The Doctor falls unconscious.

When The Doctor awakes he finds himself restrained in a Correction Centre alongside a similarly incarcerated man named Bisham. Despite the prospect of being tortured The Doctor is more concerned for Leela, whom Mandrel threatened to kill if The Doctor did not return. The Doctor though is unaware that Leela is more than capable of looking after herself and her standing with the rebels further improves when Cordo, who evaded capture, returns to the Undercity with news of The Doctor’s capture. The Doctor finds himself being questioned by Gatherer Hade, who eventually decides to release The Doctor and have his movements tracked, believing he will lead them to the heart of the conspiracy against The Company. Unaware he is being tracked The Doctor returns to the Undercity only to find that Leela, K9 and Cordo have left the Undercity in an attempt to rescue him.

On discovering that The Collector is keeping the citizens in line by the use of a calming gas, PCM (pento cycleinic-methyl-hydrane), which is distributed via the air conditioning system throughout the complex, The Doctor persuades the rebels to start a revolution against The Company. Their first target will be the main control area where the PCM is added to the air supply. Mandrel and his gang are also persuaded to start destroying the monitors throughout the Megropolis and to start spreading the message of the organised revolt.

Gatherer Hade and Marn

Unaware of The Doctor’s release Leela, Cordo and K9 attack the Correction Centre to try and rescue The Doctor but only succeed in freeing Bisham. However, as they depart the Centre they find all their possible travel routes blocked by Inner Retinue troopers. Leela leads her friends in an attack on the guards, but in the skirmish she falls from a troop transporter they have commandeered. The captured Leela finds herself in the presence of The collector who deduces from interrogating her that Gatherer Hade’s conspiracy theory is unfounded and orders that Leela to be steamed to death in a public execution. However, due to the public announcements The Doctor learns of Leela’s fate and so heads off to rescue his companion from the steamer, but he does not have much time.

Because the production of the PCM gas has been stopped more of the enslaved workers become aware about the state of affairs and so rise up against The Company and a group of former workers even gang up against Gatherer Hade who is hurled to his death from the roof of Megropolis One.

Meanwhile after rescuing his companion, in the nick of time, The Doctor and Leela head for The Collector’s Palace, and there The Doctor sabotages the computer system by programming it to apply a 2% growth tax. The Collector then arrives and is challenged by The Doctor, who denounces his operation on Pluto. Furious at The Doctors meddling The Collector tries to gas the population of Pluto but is stopped when Cordo and some of the rebels arrive and help The Doctor defeat the remaining members of the Inner Retinue.

Taunted by The Doctor, The Collector then checks his computer to find The Doctor’s re-programming has resulted in a projected bankruptcy. Unable to cope with making a loss, and because of the revolution, The Collector reverts to his natural form - a type of poisonous fungus - and is rendered harmless when The Doctor seals him in a compartment at the base of his wheelchair. The Doctor, Leela and K9 then depart in the TARDIS leaving Cordo, Mandrel and the others to contemplate re-colonising Earth which by now has renewed itself.