Vibrations begin to sound through the city as the pressure builds in the heat exchanger. The Collector is annoyed with the noise -- he won't be able to hear Leela's cries.
The Doctor finally breaks in and releases Leela. Mandrell caves in and calls to the Doctor over the microphone, telling him the chamber will blow soon. The Doctor destroys the microphone but it is too late -- the audience has heard. The Collector orders his guards to investigate.
Mandrell finally releases the pressure, unsure of whether the Doctor made it out or not. Sounds from the vent let them now he is alive and they let him and Leela out. The Doctor is angry that he used the radio link.
Bisham tells the Doctor the PCM is already clearing from the air. The Doctor asks where the public video is run from and is told it is in the Collector's office. The Doctor proposes that if they announced a successful rebellion, the people would believe it. The Collector's Palace is usually guarded by his Inner Retinue but most of them are with him in the execution chamber.
A couple of guards wander in and are caught. The Doctor expect a full attack and tells them to hold out as long as they can. He leaves with Leela, telling K-9 to help the rebels.
The Collector is upset that he received no satisfaction from the execution -- and they gave the workers a holiday for it. They will have to make it up with unpaid overtime.
A guard reports there have been minor disturbances -- workers refusing to leave their dormitories. A division of the Inner Retinue will be needed to settle the matter and more taxes raised to pay for it. The Collector is convinced that the Doctor is behind this. He tells Hade to investigate Main Control.
The rebels in Main Control are giddy now that they are freed of the PCM. Mandrel tries to keep them focused on the rebellion.
A group of guards tells some lounging workers to get back to their jobs. But Goudry and Veet encourage the workers to strike. They tell the guards they can join or leave. The guards try to arrest them and are grabbed by the mob.
Leela knocks out the guard in the Collector's office. She wants to kill him but the Doctor stops her. She reminds him that the last one she spared raised the alarm but he hypnotizes the guard to sleep. Unfortunately, he puts Leela to sleep too. He covers the guards ears and tells her to wake up. Leela shows him the Collector's desk.
Hade reports that the situation is getting bad. There is laxity an weakness everywhere, which the Collector believes is the result of too much kindness. The guards are outnumbered, reports Hade, and he will need two divisions of the Inner Retinue to quell the rebellion. Marn then reports that workers are on the roof gazing at the Sun. Hade is outraged -- the sun too good for them!
The Collector decides to return to his Palace and implement his contingency plan. He has his Inner Retinue guard his return.
As the Doctor tinkers with the Collector's computer, Leela finds a safe. The Doctor uses the sonic screwdriver to break into the vault but hesitates going through the door. Leela rushes in and is knocked out by a bolt of electricity. The Doctor deactivates it and makes sure she's all right.
The PCM levels continue to drop. An announcement on the PA claims that the Megropolis is under the control of the revolution. Guards are ordered to lay down their arms and join the citizens. Marn is corned by a group of citizens and elects to join.
Cordo comes into the Main Control and fires his gun into the roof in celebration. Bisham reminds him that they haven't really won -- it's just the Doctor trying to encourage people. They decide to take the fight into the streets, leaving K-9 to defend Main Control.
The Gatherer reaches the roof and demands that the workers leave. Veet spurs them on and they grab Hade and toss him over the railing to his death. They boast they'll do the same to the Collector when they find him.
The Collector returns as the Doctor investigates the safe. The little man is hardly surprised to see the Doctor there. The Doctor sits next to him and explains that he's not going to kill him, just shut him down. The Collector craftily offers him the Company prospectus, hoping to pique the Time Lord's interest.
The Collector hits the alarm but the the button just pops out humorously -- the Doctor disabled it so they wouldn't be disturbed. The Collector asks for terms and the Doctor asks about the Company. The Collector happily explains that Company is based out of Usarious. The Doctor recognizes the planet and remembers that it is inhabited by poisonous fungi.
The Collector tells him that the Company was looking for property and Earth was running out of resources. So they made a deal. They moved all the people to Mars, terraformed the planet and then taxed the life out of them. Pluto was the next step. But once Pluto runs out of resources, they will simply let humanity die out. They aren't that profitable anyway. The Doctor, outraged, calls him a blood-sucking leech. The Collector retorts that economics are far more profitable than war.
They hear shots approaching but the Collector is certain the revolution will be quelled. The Doctor tells him to wake up, accidently reviving the guard. The Collector tells him that if they can't quell the rebellion, all the people will die. As the guard holds his gun on the Doctor, the Collector explains that his contingency plan will release a deadly poison in the Megropolis killing everyone within 10 seconds -- except for the Collector, of course, who doesn't breath.
The guard, hearing this, hesitates and Leela, having revived, knocks him out with her knife. The Collector reaches for the death switch but Leela slams the door on his hand.
The Collector begins to sputter and stammer. He turns green as the computer reports the planet is no longer profitable. Cordo arrives with the mob and tells the Collector, in the name of the works units -- people, reminds Leela -- to surrender.
But the Collector, facing a negative profit spiral, shrinks down, turns green and reverts to a small fungus that trickles through a hole in the chair. The Doctor explains that this is the Collector's natural state and the image was needed because no one would take orders from a lump of seaweed. He corks the hole, trapping the Collector in his chair.
The Doctor, back on the roof, bids farewell to the rebels. He promises to visit once they've resettled Earth -- which should be replenished by now.
Back in the TARDIS, he promises to continue his chess game with K-9, who reminds him it is mate in six. The Doctor explains that he put a negative tax into the Collector's computer that caused him to project negative profits. This upset the little creature so much that he lost control.
The Doctor takes off and the TARDIS lurches violently, throwing the chess game to the floor. The Doctor apologizes to the irritated robot.