Beneath the towering citadel, a group of men are gathered in a mine. The stripe-haired men are pushing a complex technological device. Suddenly, a strange humming noise is heard. A roar rips through the air and the men flee before the terrifying visage of Aggedor -- the royal creature they worship. A bright red light strikes one miner and he falls to the ground dead. The remainder flee in horror.

In another part of the mine, the silver-clad Federation chief miner -- Eckersley -- is inspecting a lump of rock. The rock glows amber and he says with satisfaction that this is precisely what they need. A centaur-like creature -- Vegas Nexos -- worries that the mining is going so slowly. But at least the natives have agreed to use the sonic lance.

But just as he says this, the terrified miners rush by. They stop one -- Ettis -- and e babbles that Aggedor appeared to them, angry over the blasphemous use of the lance in his holy mountain.

Later, the Federation representatives meet with the rulers of Peladon in the ancient throne room. The high priest and chancellor -- an older red-and-silver haired man named Ortron -- leads the discussion. The beautiful red-headed queen -- Thalira -- listens attentively as he tells Eckersley that his people will not work out of fear. Eckersley relates the tale of Aggedor's appearance but is dismissive, which angers Ortron. Alpha Centauri -- a green one-eyed hexapod -- tries to mollify the chancellor.

The queen asks if Aggedor actually appeared but Nexos says that the Pels are primitive and superstitious. He thinks it is the work of saboteurs to keep the Pels from using the equipment. He explains that the sonic lance alone would increase their mining efficiency ten fold.

Thalira suggests they demonstrate the equipment to the miners to assuage their fears. The Federation people agree and thank her for her help, Alpha Centauri adding that the sooner they can get enough trisilicate out of the mines, the sooner they can end the war.

After they leave, Ortron objects to the queen attending the demonstration, fearful for her safety. She explain that she wants to fulfill her father's dreams of Federation membership. He expresses his support for her but reminds her that they will have to make some sacrifices to make progress.

Later that night, as Ortron offers prayers up in the temple to the statue of Aggedor, a guard hears a strange sound in he mines. He watches in astonishment as the TARDIS materializes before his eyes. Out burst a tall gray-haired man and a pretty young woman -- the Doctor and Sarah Jane Smith. The Doctor is boasting about how much the Citadel of Peladon will impress Sarah. But she is less than impressed to find herself in "another rotten gloomy old tunnel." They decide to find out where they are and start walking through the mines, watched by the hidden guard.

The Doctor thinks they are on Peladon but have just missed the Citadel. Sarah isn't so sure and wants to go home. But the Doctor explains he has wanted to return for a long time and check up on his friend, the King.

At that moment, Eckersley, Nexos and the miners are setting up the lance. When the queen arrives, she is greeting by Gebek, the chief miner. He is confident the demonstration will placate the miners. But Ettis leaps in and begs the queen to not allow this blasphemy. Nexos repeats his belief that the appearances of Aggedor are the work of spies. Gebek muses that the guards saw some aliens earlier. Ortron immediately orders the guards to find and destroy the aliens.

The Doctor is having trouble finding the Citadel. Sarah against wants to go back but the Doctor resists. He still wants to see the King -- and he has to admit he is lost.

The lance is ready. Nexos activates it and a section of wall shimmers, distorts and explodes, leaving a cleanly cut tunnel to main seam of trisilicate. But the moment of triumph is stopped by the strange hum. The miners back off but Nexos strides forward confidently. The bright red light shines on him and he drops lifeless to the ground while the miners run for their lives.

The Doctor has now wandered into a familiar part of the tunnels. But guards suddenly appear. Before the Doctor can speak, Sarah runs for it. The Doctor follows and they find one of the secret doors. It opens up into the Temple of Aggedor.

Sarah is impressed by the Temple. The Doctor starts to tell her the story of his last visit but is interrupted by the arrival of the guards through the secret door.

The time travelers are brought into the throne room. When Thalira and Ortron arrive, they are made to kneel. Ortron promptly accuses them of sabotage and blasphemy. Sarah tries to answer but is silenced. The Doctor first asks for their names and gives his respects to them.

He then asks about King Peladon. Thalira explains that he was her father but died when she was a child. The Doctor tells her that he was friends with Peladon and introduces himself. Thalira recognizes his name but Ortron is still suspicious.

Just then, Alpha Centauri arrives. It recognizes the Doctor immediately and they greet each other with delight. Centauri tells Thalira that it doesn't know the female -- adding that she's of no important (to Sarah's annoyance). But this is definitely the Doctor. Ortron still thinks the aliens are dangerous but Alpha Centauri says it will vouch for them. Thalira overrules Ortron and releases the Doctor and Sarah into Alpha Centauri's custody. Sarah starts to demand an apology for their treatment but the Doctor quickly drags her out of the throne room.

After they leave Ortron reiterates his distrust of the Doctor. He reminds the queen that it was the Doctor who got them into the Federation in the first place. Thalira replies that they won't learn anything by killing him. If he is an enemy, he'll reveal it sooner or later.

Gebek is with the miners. He wants to talk to the queen about the work conditions, but Ettis objects. He thinks she is just a puppet of the Federation. The miners want to start fighting their rulers but Gebek insists that they try to work with the queen. After he leaves, Ettis tells the miners they will wait until Gebek is meeting with the queen -- and then they'll start fighting.

Sarah Jane is still fuming over their treatment -- especially Alpha Centauri's remark that females are of no importance -- as they walk through the halls of the Citadel. The Doctor points out that Alpha Centauri did save their lives. As they pass a curtain, it parts to reveal Ettis and his miners.

Gebek approaches Ortron who tells him he is not allowed to see the queen. But Gebek is insistent, saying his task is too urgent to formally request an audience. Ortron relents and lets him in. Gebek asks the queen to send the Federation aliens away.

But even as he speaks, Ettis and the miners have found the armory. They attack the guards and start to break in.

The Doctor has reached the communications room and is speaking to Eckersley. He thinks that the Federation has only brought this trouble on itself -- Peladon has seen no progress in the half-century of Federation membership. Alpha Centauri objects that the Pels oppose change.

Eckersley then explains that their need for trisilicate is desperate. The Doctor asks about the war, pointing out that the Federation is supposed to be peaceful. Alpha Centauri explains that they have been attacked by Galaxy Five and their attackers refuse to negotiate a peace. Trisilicate is the basis of all the Federation's technology and thus the supply of it is critical. It would be in the interest of Galaxy Five to disrupt that supply.

They are interrupted by an alarm. Eckersley switches on the monitor and see that the miners are attacking the armory. They've broken through the outer wooden door but run up against an impregnable metal one. Ettis tells Graber to get an alien to open it for them.

Eckersley is curiously unconcerned about the attack. The armory door is solid duralinium and Ortron will soon dispatch his guards to deal with the problem. Sarah is appalled that he can be callous about the miners getting killed. Just then, a miner bursts in with a knife. He demands that Eckersley open the door for them. But the Doctor attacks and overpowers him.

Despite the attack, the Doctor is still sympathetic to the miners. He wonders why they are resorting to such tactics. He decides to take his attacker before Thalira. After they leave, Alpha Centauri approaches Sarah who jumps at the sight of the hexapod. Centauri laments that its appearance is frightening to humans but Sarah reassures it that she's just nervous.

In the throne room, Ortron explains to Gebek that it is for the rulers to make all decisions on Peladon. Gebek warns him that there may be a rebellion, which alarms Thalira. Gebek quickly assures her of his personal loyalty. But just then, the guards arrive and inform them of the attack on the armory. The Doctor then comes in with his prisoner.

Ortron now believes Gebek has betrayed them and wants both thrown into prison. The Doctor objects but Ortron is insistent that they must be executed for treason. The Doctor gets into a fight with the guards, during which Gebek escapes. Ortron gloats that the Doctor has shown his true colors. Since he is clearly in league with the miners, he will die in their place. The Doctor points out that had they killed Gebek, he would have become a martyr for an immediate rebellion. He again offers to help -- specifically in proving that the Aggedor appearances are a trick.

Thalira agrees to this, greatly angering Ortron. The Doctor asks to see where the last appearance of Aggedor was and she send her champion Blor to escort him. The gigantic mute champion leads the Doctor away. Ortron, furious at the queen's defiance, leaves as well. Outside, he tells the guards to captured or kill Gebek and his allies.

Ettis, meanwhile, has placed explosive in the mine to seal up the tunnel carved by the sonic lance.

Eckersley tells Sarah about the Doctor's confrontation in the throne room. She worries that he has only talked himself into more trouble.

The Doctor and Blor go into the tunnel, over the objections of the reluctant champion. The Doctor can see that the trisilicate vein is very rich. No wonder it is of such importance to the Federation.

Ettis watches all this. He is delighted that he will be able to kill an alien and the queen's champion.

But then it disappears just as suddenly as it came. The Doctor begins to dig himself out.

Outside, Gebek is furious with the miners. Ettis tells him that they have simply given the cave back to the sacred mountain -- and trapped the aliens in the bargain. Gebek is appalled when he realizes that Gebek has trapped the Doctor -- his only real ally. Quickly, he starts to the dig the Doctor out. His fellow miners hesitate for a moment but then join in.

But the stones are too big and heavy to be moved by hand. Gebek hits on the idea of using the sonic lance to re-open the cave. His fellow miners object but he begins tinkering with it. It starts to power up. The Doctor hears the lance inside the cave and divers for cover. The walls distort and a small hole is blown through the wall of rock. It is in the nick of time -- with a humming sound, Aggedor returns to finish off the Doctor. He nimbly leaps through the hole in the rock as it blazes at him, escaping its lethal blast just in time.

Sarah is just thinking that the Doctor has been away too long when an emergency sounds about the explosives. She decided to look for him but Alpha Centauri thinks they should wait for help. Sarah is undeterred, however, and races to the mines while Alpha Centauri calls Eckersley for help. Sarah dashes into the temple, through the secret door and into the mines.

The Doctor has told Gebek and Ettis his story. He offers to help but Ettis is skeptical. The Doctor explains that they must find out the truth of Aggedor for the good of all Peladon. He tells them if they go back to work, he will try to persuade the Federation to improve working conditions. Ettis repeats that they will not work while Aggedor is angry but the Doctor counters that this is probably why their enemies are using Aggedor in the first place.

Their conversation is interrupted by the arrival of palace guards. A fight breaks out between the miners and guards. Even as Sarah closes in on the Doctor, he knocks out the guards and runs away with the miners.

Sarah has taken a wrong turn however and comes upon a metal door and a diffusing window in the mine. She sees a shape moving behind the window and calls for help. But the shape disappears and the lights go out behind the window. Sarah is about to knock on the door when she is suddenly enveloped in swirling colors and a blazing alarm klaxon.

Eckersley arrives in the communications room. He realizes that Sarah has triggered the refinery alarm. He turns it off and the young woman collapses. Alpha Centauri wonders if Sarah is hurt and Eckersley says that if she was there too long, her mind could be seriously affected. He rushes out to lend aide.

Gebek, the miners and the Doctor have stopped in a safe passage. The miners tell the Doctor of their lives -- all they do is work and sleep, earning barely enough to feed their families. Membership in the Federation has made things better for the nobles, but not for the miners.

The Doctor again states that the appearances of Aggedor are a trick. He advises the miners not to try anything else -- but lets slip that the armory doors are controlled from the communications room. When he says this, Ettis looks like a man with an idea. The Doctor advises them to return to work and he will help them. Gebek agrees and orders the miners to stop their violence -- they reluctantly concede.

The Doctor asks Gebek if it is possible to meet with Thalira without Ortron. Gebek agrees to lead him to a secret passage. After they leave, Ettis decides they should attack anyway -- and this time open the armory door from the communications room.

Sarah wakes up as Eckersley arrives. She appears to be all right. She tells the miner that she saw someone in the refinery but he explains that she must have hallucinated because of the alarm -- the refinery is empty. They return to the communications room. But as they leave, a faint green shape appears in the refinery window.

The Doctor's way to Thalira is blocked by the guards. A young miner named Preba leads some away and the Doctor and Gebek knock the rest out.

Ortron explains to Thalira that the Doctor must be her enemy. Blor is dead and he has been seen with Gebek. Thalira wants to believe in the Doctor but the chancellor pushes her to crush the mine rebellion and execute the Doctor.

Sarah, meanwhile, is having an argument with Eckersley. She chides him for putting such a dangerous alarm at the refinery but he reminds her that Peladon is a dangerous place. Just as he is explaining about the need to show the miners how progress will help them, Ettis leaps out from hiding. he knocks out Eckersley and captures Sarah and Alpha Centauri. He takes them to the communications room and demands that they open the armory. At first Alpha Centauri refuses but Ettis threatens to kill Sarah.

Gebek is leading the Doctor into the Citadel to negotiate even as Ettis' miners attacks the armory guard. Alpha Centauri operates the controls to open the metal doors. But this set off an alarm.

Ortron, hearing the alarm, races to Thalira to inform her that the armory is being raided. The rebellion has begun! He laments that this is what comes of softness with the common people.

The miners emerge from the armory with federation blasters and gun down the queen's guards.

Ettis is furious that Alpha Centauri has set off the alarm, but the hexapod pleads ignorance. As he is about to stab the ambassador, Sarah stops him and tells him he should run. He agrees -- but takes Sarah with him as a hostage. A frantic Alpha Centauri then goes into the hallway and wakes up Eckersley.

Sarah manages to squirm free from Ettis as they are about to enter the mine. But she is promptly captured by Ortron.

In the mines, Ettis runs into Gebek and delightedly crows that they've won. Gebek decides he needs to go with them to prevent more violence and the Doctor goes into the Citadel on his own.

Eckersley, recovered from his attack, worries what will happen now that the miners are armed. Alpha Centauri is distraught that it opened the door and explains to Eckersley why it did. The guards report that Sarah has been recaptured and Ortron thinks she was working with the rebels.

Sarah is desperately trying to explain events to Ortron, but the chancellor is determined that she is in league with the rebels. He points out that the armory was opened because of her. As he speaks, the Doctor lets himself into the temple through the secret passage and tries to defend Sarah. But Ortron turns the tables on him and gets him to admit talking to Ettis in the tunnels.

The Doctor tries to explain that their only choice is to ally with Gebek. He wants to discuss this with the queen but Ortron says he will handle this himself. He begins praying to Aggedor for advice.

Alpha Centauri tries to explain to the queen that Sarah was a victim of the rebels. Eckersley wonders if it was a put-up job. The Queen decides to trust Alpha Centauri but points out that in the Temple of Aggedor, Ortron has absolute authority.

Ortron has come to a decision. Since the Doctor and Sarah have blasphemed against Aggedor, they will be punished by him.

Alpha Centauri pleads with Queen Thalira, but the young woman is insistent that she has no real power. The hexapod quietly suggests that perhaps it is time that this changed. Encouraged, Thalira goes with the ambassador to the temple.

Ortron's guards move an altar to unveil a pit. The Doctor and Sarah are pushed forward even as Thalira tries to get past the guard. She finally gets into the temple but not before the time travelers are thrown into the pit. Thalira is furious but Ortron insists that they will now face the judgment of Aggedor.

But even as Thalira is demanding that Ortron rescue them, the Doctor is trying to calm the animal. Remembering their earlier encounter, he takes out a watch and begins singing a lullaby to the best as he swings it through the air. It immediately calms down and they are able pet the furry, purring creature. The Doctor then calls up Ortron, demanding to be released -- an order echoed icily by the queen.

Alpha Centauri crows to Eckersley that the Doctor has been exonerated. But the Federation miner remains pessimistic now that the miners have Federation weapons. He thinks they should call in Federation troops to help. He points out that if things go badly, Alpha Centauri would be held responsible. The hexapod wants to talk to the Doctor before making any decisions. But when Eckersley realizes that the sonic lance is an incredibly dangerous weapon and runs off to secure it, this frightens the ambassador enough to make it send out an urgent radio message for help.

In the throne room, Thalira is furious with Ortron. She tells him that the Doctor must now be considered vindicated. The chancellor, unused to such headstrong behavior from the queen, stomps out.

Thalira asks the Doctor and Sarah to join her for refreshments. As they eat, the Doctor explains that the miners on the verge of rebellion and Gebek is the only moderate. He explains that it is Ettis and his followers who raided the armory. He strongly advises her to meet with Gebek and offer better working conditions. She replies that Ortron thinks this will just make the miners demand more. But Sarah thinks that Ortron just wants to keep the benefits of Federation membership for the nobles.

Thalira agrees to try to work things out and asks the Doctor to bring Gebek to her in secret. He leaves to do so but asks Sarah to stay and talk to the queen.

After he leaves, Sarah starts talking to Thalira about women's liberation. Thalira explains that Peladon has always been ruled by men -- she was only chosen because her father died young with no male children. She explains that Ortron has all the real power since she is "only a girl". Sarah replies, "There's nothing only about being a girl." She says that one way or another, Thalira is the queen and she should let them know it.

Ettis and Gebek are arguing, with the younger man insisting they should now assault the Citadel itself. Gebek points out that they can't take on the entire Federation with a handful of guns.

The Doctor, meanwhile, is angry that Alpha Centauri has called for troops. He thinks it will only the situation worse. Sarah arrives and tells the Doctor about her experience at the refinery. She thinks that if someone were causing the Aggedor tricks, the refinery would be a perfect place to do it from -- they would have power, technology and secrecy. The Doctor agrees to investigate but wants to talk to Gebek first.

Ortron overhears this in the corridor and tells the Doctor he is to stay in the Citadel until the investigation is complete. Clearly, he still thinks of himself as having all the power.

He goes into the hall and waits. When the Doctor slips out anyway, Ortron's men follow him. They, in turn, are followed by Sarah.

The Doctor opens the secret door and the guards spring out and arrest him. Orton orders the Doctor to be taken to the dungeons. After they leave, Sarah takes the secret passage, determined to carry out the Doctor's mission for him.

Gebek and Ettis watch from hiding as Eckersley tries to secure the sonic lance. Sarah arrives and, trying to keep her motives secret, tells Eckersley the Doctor wants to make sure the lance was secured from the rebels. The hiding miners want to attack but Gebek tells Ettis to wait a moment.

Alpha Centauri is again protesting to the queen over the treatment of the Doctor. Ortron insists that Thalira told him to investigate the rebellion but Alpha Centauri replies that the Doctor has Federation protection. Ortron then craftily points out that the Doctor has no official identify. But Thalira, inspired by Sarah's talk, tells Ortron that she has given the Doctor her personal protection.

Ortron insists that the Doctor remain in prison and Sarah be arrested. But the queen surprises him by standing her ground, insisting that at least Sarah remain free. Ortron agrees but says it is only because Sarah, being a female, is unimportant.

Ettis finally launches his attack on the lance. Eckersley swiftly activates the device, making the cave collapse. But Gebek has snuck up behind the Federation man and forces him to stop. Sarah now explains to Gebek that queen wants to meet with him and he agrees to come at the earliest chance. He then sets Eckersley free over Ettis' objections. But he has the miners secure the lance.

Back in the throne room, Eckersley tells the queen that the lance, at full power, could wipe out the entire Citadel. Alpha Centauri tries to assure everyone by telling them Federation troops are on the way but this only infuriates everyone. They don't want outside interference.

Sarah comes up with a plan. If they all pretend everything is fine while the troops are there, the Federation soldiers will quickly leave.

In the prison, the Doctor tries a trick to get the keys off the guard, but fails.

Sarah and Alpha Centauri are delighted that Ortron has agreed to her plan to fool the Federation troops. She then decides to break the Doctor out of the dungeon.

Gebek sneaks into the Citadel to meet with the queen, but runs into Sarah. He advises her to return to the queen -- he'll rescue the Doctor.

While the Doctor distracts the guard with a magic trick, Gebek sneaks up and knocks the man out. The Doctor asks Gebek to lead him to the refinery -- he is now convinced that Sarah is right and it is the source of their troubles.

As they race to the refinery, Ettis finds a rocky outcropping and points the sonic lance at the Citadel.

Gebek explains to the Doctor that the Pels will rebel if Federation troops arrive. The Doctor agrees but decides he needs to expose the Aggedor fraud first. They hide and see miners walking through the tunnels, followed by armed guards. Gebek is outraged - his men won't work if they are under constant guard.

In the communications room, a hissing rasping voice on the console tells Alpha Centauri, Sarah and Eckersley that the troops will be landing soon. They wonder among themselves if the ruse will last long enough to fool the troops.

Gebek leads the Doctor to the refinery but warns him about the alarm system. The Doctor uses his sonic screwdriver to open the alarm box and begins to tinker with it.

Eckersley, worried about the location of the lance, begins to check the surveillance monitors. He spies Ortron talking to the miners; then sees the Doctor and Gebek breaking into the refinery.

Alpha Centauri suddenly wonders if the Doctor is, in fact, in league with the rebels. But Sarah explains their theory that the Aggedor fraud is being run out of the refinery. Eckersley thinks this is ridiculous.

Ortron, meanwhile, is talking to the miners. He tells them about the Federation troops and explains that their only choice is to act as though everything is fine. He appeals to them for the sake of Peladon. He promises that they will have a fair hearing of their complaints once the soldiers are gone. The miner are clearly skeptical, but agree to go back o work. But suddenly, the image of Aggedor appears and blasts down another terrified miner.

At the refinery, Gebek hears the panicked cries. The Doctor finishes his burglary as the miners rush past in a frenzy of terror. But just as he finishes, the silver refiner door opens.

The Ice Warrior does not fire, but takes the Doctor prisoner. Eckersley is watching on the monitor when the Martian commander -- Azaxyr -- strides into the communications room and informs them that the planet is now under martial law.

The miners explain to Ettis that Gebek is meeting with the queen. The young man thinks its a trick but won't do anything about it. This angers the other miners and he is forced to agree to rescue Gebek.

Azaxyr sums up the situation in the throne room. Ortron claims there is a rebellion; Gebek says they have been cheated by the nobles. Ortron says the Doctor is a spy; Alpha Centauri says he is an old friend. Gebek says that Aggedor appears because he is angry; the Doctor says it is a trick.

The Doctor jokes that Azaxyr should be a judge. The Martian coldly responds that under martial law, he *is* judge, jury and executioner.

Azaxyr notes that only Eckersley hasn't said anything and the miner replies that he just wants to do his job. This pleases the Martian commander. He doesn't care what the situation is on Peladon -- all he cares about is getting the trisilicate. Of course, the Doctor reminds him that the situation is what is causing the problems getting trisilicate. The problems can not be separated.

Azaxyr proposes that the miners work under Ortron's armed guards -- and that the guards kill anyone who refused to work. Both Gebek and Ortron refuse to obey this command but Azaxyr tells them he has taken hostages and will start executing them if the miners do not go back to work.

Ettis has led the miners to the brink of the Citadel. He has formulated a plan. They will tell the Federation to leave or they will destroy the Citadel with the lance. After they go through the secret door, they capture a guard and demand to be taken to Gebek.

Thalira is protesting against the Federation's brutal methods. Alpha Centauri chimes in that the Federation never uses such methods. But Azaxyr reminds them that they are at war -- he must get the trisilicate at any cost.

The Doctor, prompted by Sarah, asks what will happen if the terror tactics don't work. Azaxyr informs him that they will simply bring in Federation miners and do the work themselves. This unites all the Pels, who state flatly that they will fight any occupation. But the Martian commander is unfazed, angrily telling them that his space fleet would respond by blasting the planet to pieces. He then reiterates that he wants a peaceful solution.

Just then, Ettis' men burst in and call out the Gebek. The Ice Warriors whirl and open fire, mercilessly gunning down the miners. Only Ettis is untouched and he flees for his life.

The Doctor and Gebek kneel over the bodies as Azaxyr apologies for the massacre. He hopes another demonstration will not be necessary. He orders his lieutenant -- Skkel -- to take everyone to the communications room. As he leaves, Thalira and Ortron join Gebek kneeling over the bodies of the miners. Ortron vows revenge for the slaughter.

In the communications room, Azaxyr tells the Doctor he's not sure what to make of the time traveler -- he should probably just let Ortron proceed with the execution. Alpha Centauri says that Federation regulations forbid it but Azaxyr again replies, "I am the law." The Doctor asks if he will get a trial but the Martian replies that he just had it.

The Doctor then tells Azaxyr that it would be foolish to kill the one man who can help -- he is the only one Gebek trusts and Gebek is the key to the miners. Alpha Centauri and Eckersley hurriedly back up the Doctor's claim. Azaxyr relents and agrees to let the Doctor talk to Gebek -- but reminds the Time Lord he will be killed if he fails.

Eckersley and Azaxyr leave for the refinery. Sarah is angry that Eckersley is so callous. She's so frustrated she suggests just finding the TARDIS and leaving. But the Doctor reminds her they don't know where the TARIS is -- and besides, they can't abandon their friends.

The Doctor then asks Sarah about her visit to the refinery and if Skkel looks familiar. Sarah realizes that the Ice Warrior is the shape she saw behind the refinery window. Alpha Centauri is skeptical but the Doctor is now sure the Ice Warriors were in the refinery the entire time. They must have an agenda of their own. This shocks the gentle Ambassador -- that would be treason!

The Doctor leaves to talk to Gebek, Skkel reluctantly letting him past. Alpha Centauri decides to report Azaxyr's actions to the Federation but, as Sarah guessed, the communications lines are being jammed by the Martian fleet.

The Doctor arrives in the throne room. He tries to persuade the Pels to work with Azaxyr but all three now want to resist the occupation. The Doctor then comes up with an idea -- they will pretend to cooperate long enough to buy some time.

Gebek gives a speech to the miners in front of the Ice Warriors. He cleverly lets them know that they are to cooperate -- just as they always have with "our good friend Ortron". Just as they did over the armory and the sonic lance. The miners clearly get the point and agree to cooperate.

Azaxyr congratulates the Doctor on his success. He says that he has suspended the death sentence but still doesn't trust the Doctor. He reminds the Doctor that his only chance of survival lies in cooperation before sending him back to the communications room.

When the Doctor gets to the communications room, he starts examining the controls. Sarah warns him that Azaxyr will kill him at the first sign of treachery, but the Doctor knows that Azaxyr will kill him sooner or later. He has to strike first. And he does so by turning up the heat in the mines.

While the miners work, Ettis sneaks in and talks to Preba. He is furious they are working. He's convinced Gebek has betrayed them all and he's decided to blow up the Citadel with the lance. Preba tries to stop him but the insane Ettis stabs him and escapes.

As the Doctor and Sarah watch the mine thermostat rise, the Doctor explains that the Martians will faint from the heat.

Gebek notices the Ice Warriors are getting woozy. He asks a palace guard if they are ready to attack. The Ice Warrior then asks why it is so hot. Gebek explains that it is always hot. "If you can't stand the heat, keep out of the mine."

Ortron briefs Thalira on the plan. She's hesitant to endanger her people but Alpha Centauri reassures her. Azaxyr enters and Thalira tells him she will be making a formal complaint about his behavior. The Martian leader hisses that they can't use the communications lines until the emergency is over. She argues that the crisis is over -- the miners are working. But Azaxyr is suspicious of how well things are going.

Gebek finally gives the word and the miners fall upon the sleepy Ice Warriors. The Doctor and Sarah see this happening and call Skkel over to alert him. While the lumbering Martian stars in shock at the screen, the time travelers escape. Sarah worries that Azaxyr will send more troops into the mine but the Doctor reminds her the warriors will simply pass out from the heat, leaving the Citadel undefended.

As the fighting continues, Gebek finds the wounded Preba. Preba quickly tells him about Ettis. The Doctor arrives, is told about Ettis and decides he will handle that problem. Gebek needs to lead the miners. The Doctor grabs a sword and goes off in pursuit of Ettis while the Pels continue to pummel the defenseless Ice Warriors.

Skkel manages to capture Sarah and drags her back to the communications room. Azaxyr and Skkel start to interrogate her.

The Doctor arrives at a rocky cave overlooking the Citadel. He tries to talk Ettis out of firing -- explaining that the Pels have united to fight the Ice Warriors. Ettis doesn't believe him. Instead, he draws his sword and attacks.

Sarah finally tells Azaxyr about the sonic lance. He calmly replies that he knows all about the lance. He turns on the monitor and watches Ettis and the Doctor fighting. He explains that he has already set the self-destruct on the lance. Even if Ettis wins and fires the lance, he will simply blow himself (and the Doctor) to kingdom come!

Sarah can only stare in horror at the monitor screen as Azaxyr assures her that the Doctor's death was an unfortunate necessity. But a bitter Sarah points out that he hasn't won yet -- the rebels control the mines. The Martian commander, however, has already turned off the heat. And when Eckersley arrives, Azaxyr decides to shut off the mine ventilation system.

Sarah tries pleading with the Federation commander, arguing that many miners will be killed if they leave the mines -- just as the Doctor already has. But Eckersley is determined not to join the Doctor and leaves to do Azaxyr's bidding.

One the mountain, the Doctor blearily crawls to his feet. He looks sadly at he wrecked lance and the body of Ettis before wandering back toward the mine. He runs into Gebek and the Doctor sadly explains what happened. Gebek tells him that the Ice Warriors have retreated from the mines. But the heat has been shut off and the air is getting stale. He also reports that Sarah has disappeared.

Thalira tries to comfort Sarah for the loss of the Doctor. Ortron assures her that the Doctor may have escaped -- which only reminds Sarah of the Doctor's relentless optimism.

Alpha Centauri returns to inform them that Azaxyr is planning to extend martial law over the entire planet. Sarah wants to inform the Federation but Alpha Centauri only has the emergency distress beacon. To activate it, though, they would need to get past the Ice Warrior guard on the throne room.

Ortron remembers the secret passage in the throne room. But it is in view of the Ice Warrior. Thalira points out that the Martian is too slow to stop them all. She wants to join her people in the mine, although Ortron doesn't want her endangered. But he finally agrees, shamed by her courage.

Alpha Centauri reports to the Ice Warrior guard that the queen has fainted. When he goes in to check, Sarah pushes him and they all run. Unfortunately, the Ice Warrior steps on the queen's robe. Ortron tries to help her but is gunned down by Skkel. Azaxyr then returns and demands to know where the others have gone. Thalira tells him they've returned to the mines. He then taunts Thalira about the consequences of resistance. She sadly covers the dead chancellor with her robe.

The Doctor and Gebek evade the warriors in the mine and get to the refinery. They hide as Azaxyr arrives and begins speaking to Eckersley, who seems strangely pleased that that Alpha Centauri and Sarah have fled to the mines.

Sarah is pushing Alpha Centauri to activate the distress beacon, but the flustered ambassador can't remember how. It accidentally switches on the monitor and the image inside the refinery comes up. Sarah notes that the Eckersley and Azaxyr seems very friendly and turns on the sound.

As two different groups listen in, Azaxyr tells Eckersley he sees no reason to continue the masquerade -- the planet is practically theirs. He then goes on to reveal they are ready to start shipping trisilicate to Galaxy Five. The shocked listeners realize that they are both traitors!

Azaxyr wants to finish things quickly, which Eckersley assures him will happen once the air runs out and they control the mines.

Eckersley then suggests they smoke the miners out with Aggedor. With a flourish, he unveils the image that has been attacking the miners. He activates a transmat. Aggedor appears and attacks some miners, then returns to the refinery. Sarah realizes that Eckersley was deliberately making things difficult so that Alpha Centauri would call for Azaxyr's help. Then, to her delight, she see the Doctor peering into the refinery through the door. She joyously leaves to join him in the mine.

Eckersley receives a report that the miners are fleeing the mines -- only to be gunned down by Azaxyr's troops. As he works on another Aggedor appearance, the Doctor relays the truth to Gebek. Gebek wants to rush into the refinery but the Doctor restrains him. They'd be killed by the Ice Warriors. They'll go in once the coast is clear.

Soon after, the two conspirators leave for the Citadel. The Doctor and Gebek hide as Eckersley ruefully notes that because of the Doctor's sabotage, he has to reset the alarm from the communications room. They leave an Ice Warrior standing guard.

Soon after, Sarah arrives. When the Ice Warrior turns toward her, Gebek clubs the Martian down with a massive boulder. Sarah is delighted to see the Doctor but he is in a hurry to get into the refinery before the alarm is set. Sarah and Gebek drag the warrior away as he attacks the lock.

Alpha Centauri is watching this on the monitor when Azaxyr and Eckersley return. Azaxyr is immediately suspicious and then realizes that the distress beacon has been activated. He angrily threatens the ambassador but Eckersley calms him. Azaxyr agrees to give Alpha Centauri one more chance and drags it off to the control room. Eckersley then switches on the alarm -- just as the Doctor has finished disabling it.

Azaxyr tells Thalira that the mining will start again soon, using all Federation equipment. He demands full cooperation and Thalira reluctantly agrees. Alpha Centauri then blurts out the Eckersley and Azaxyr are both traitors. The Martian orders the ambassador killed but Eckersley intervenes again. He admits they are traitors, which causes Thalira to refuse cooperation. Skkel simply points his gun at the queen to emphasize the threat.

Eckersley then asks Alpha Centauri how it found out about the treachery. When they hear the story, Azaxyr realizes the queen lied to him about Sarah's whereabouts. He demands to know her location but the queen refuses to speak. He then threatens Alpha Centauri, who caves instantly. The Martian commander in enraged that the Doctor is still alive and sends Skkel off to kill the Time Lord.

The Doctor finally breaks into the refinery and switches the mine ventilation back on. He begins inspecting the Aggedor projection equipment. As he does, Skkel arrives and stars to blast the door with his sonic gun.

But the Doctor is ready for them. He operate the controls and makes Aggedor appear on the other side of the door. It attacks and kills one Ice Warrior. The others flee.

The Doctor is delighted -- now they can use Aggedor for their side!

When Skkel returns, Azaxyr boasts to Thalira that the Doctor is dead. But Skkel explains about Aggedor. Azaxyr wants to send more warriors but has none to send. Eckersley, however, quickly thinks of a way to flush the Doctor out.

Gebek talks to the shaken miners. They are terrified but he explains that Aggedor was a trick of their enemies. He is sure the beast will now fight on their side and tells them to watch for his appearance.

In the refinery, the Doctor finishes a countdown and activates the transmat.

The miners are losing patience when Aggedor appears. At first, they are scared but Gebek advances toward the apparition and is unharmed. The miners are impressed and agree to resume fighting.

Eckersley and Azaxyr watch all this on a monitor. Azaxyr swears to kill them but Eckersley reminds him that the Doctor controls Aggedor. He brings up the refinery and hears the Doctor admiring the system. He thanks the Doctor for the compliment. The Doctor asks him to give up but Eckersley explains that the security system works inside the refinery as well as out. He turns it on at the lowest level and red lights begin to flash in the Doctor and Sarah's heads.

The Doctor send Sarah to warn Gebek about the Ice Warrior counterattack while he continues to work the controls. Azaxyr goes to set an ambush for the miners while Eckersley turns up the intensity. He tells the Doctor that the communications room is shielded from Aggedor.

The miners encounter an Ice Warrior and Aggedor appears, striking down the Martian. The inspired Pels rush forward.

Azaxyr angrily asks Eckersley why the Doctor is still in control. The miner turns up the security system to maximum intensity and assure the Martian commander that it will be any moment now. The Doctor's face is sweaty and strained as he continues to work the controls.

Azaxyr follows Skkel into the hallways and sets his ambush. The miners run right into it and are killed. But Aggedor reappears and wipes out the Martians except for Azaxyr. The miners rush back into the Citadel, led by Gebek.

The Doctor finally gives in to the security system. He leans back in his chair, his face covered with sweat, and passes out.

Sarah takes a gun off one of the bodies in the hall and confronts Eckersley. She forces him to turn off the alarm but he gloats that the Doctor is already dead. As Sarah stares in horror at the screen, he takes the gun. He bitterly laments that everything was going well until she and the Doctor arrived. He seems about to kill her but then leaves, locking her in. Sarah gazes sadly at the image of the Doctor.

Eckersley hides as Gebek passes, then kills one of the miners to get away.

The rebels reach the throne room to find Azaxyr and his last soldier holding guns on Thalira. They reluctantly lay down their arms. But as Azaxyr advances triumphantly on Gebek, they jump on him, turning him around so that the blast from his sonic gun kills the remaining Ice Warrior. The Martian commander is finally stabbed by a guard and crumples to the ground, dead at last.

Gebek goes to Thalira, who seems unharmed. He tells Alpha Centauri to contact the Federation. The hexapod hurries to the communications room where it informs Sarah of the good news. But she is in tears over the Doctor and sadly walks back to the refinery.

Azaxyr's body is dragged into the hallway as Eckersley watches from behind a tapestry. Alpha Centauri returns to tell Thalira about the Doctor. The queen can't believe Eckersley could be so evil. On cue, he steps in and kidnaps the queen. He wants to use her as a hostage while he flees to a hidden shuttle. He knocks out Alpha Centauri and catches Thalira before she can escape through the secret door. He then drags her through the door at gunpoint.

Sarah arrives at the refinery and stands over the Doctor's body. She begins to cry again but, to her shock, the Doctor's eyes flutter open. "Tears?" he asks. He explains that he put himself into a coma to survive the machine. Sarah is outraged she was worried for nothing and the Doctor jokes it's like she would have preferred him dead.

Gebek and the miners return to the throne room to find Alpha Centauri knocked out. Meanwhile, Eckersley continues to drag Thalira to his escape. When the Doctor and Sarah return, Gebek is distraught. Eckersley knows the mines extremely well -- they'll never be able to find him. But the Doctor quickly gets an idea.

Eckersley pauses amidst a pile of dead bodies and the queen rebukes him for all the bloodshed he's brought to her planet.

The Doctor puts his plan into action -- using Aggedor to track down Eckersley. The Federation miner takes a wrong turn and can't find his way back before the royal beast closes in. Eckersley threatens to kill the queen, but she bites his hand, forcing him to loosen his grip.

With an angry roar, Aggedor leaps on Eckersley. He fires his gun as it bites his neck and they both fall to the ground. The Doctor sadly inspects the noble creature but both combatants are dead.

Later, Thalira is back on her throne, acknowledging her debt to the Doctor. She hopes he will stay long enough to be thanked properly. She says she needs his help but Sarah point out that she doesn't need anyone's help. Thalira then offers the Doctor a position as her chancellor but he suggest Gebek for the post. At first, Thalira objects that he's only a miner, but Sarah says, "There's nothing only about being a miner." Thalira then laments that all she can do is give her thanks. The Doctor is content with that.

Alpha Centauri then reports that the war is over. Once the trisilicate scheme failed, Galaxy Five was eager for peace.

Gebek then informs the Doctor that his blue box has been found. The Doctor decides to go check on it. He and Sarah turn to leave. But the queen, clearly aware this is the last time she will see them, wishes them farewell. They turn and bow to her. She then takes her seat and calls for Gebek to approach.