Commander Uvanov and his crew -- second in command Toos, chief fixer engineer Dask, meteorologist and scientist Chub, chief mover Poul, crewmembers Borg, Cass and Zilda -- are manning a giant Sandminer, a mobile mineral scooping machine on the windswept plains of the desert on an unnamed planet. Also on it are many silver robots, among them SV7 (a super voc), D84 supppsedly a Dum class of robots), and other robots. All look alike and all look somewhat humanoid.

Borg is getting a rubdown by robot V6 but Chub feels the need to tell him a story of Voc Therapist Robot that went haywire during such a rubdown and the robot tore a client's arm off. Dask explains that the robots have a million multi level constrainers and for a robot to malfunction all of those would have to malfunction. One of the others heard this story but thought it was a leg. Uvanov plays chess to a robot and loses -- it will have mate in 8 moves. Dask tells him the robots are unbeatable. V14 tracer robot picks up a sandstorm, putting the crew on full alert.

The TARDIS spins in space. In the old wooden control room, the first control room, Leela spins a yo-yo, asking now if she can stop. The Doctor thought she was enjoying it; she thought she was doing it as part of the "magic" of the TARDIS. They quibble a bit about "magic" and science. The Doctor tells her that to those who do not know yet, the unexplained seems inexplicable. She wants him to explain how the TARDIS is bigger on the inside than on the out. The in and the out are not in the same dimensions he tells her, not very clearly. He also demonstrates by showing her two boxes, a small and a large, then brings the smaller one closer to her, telling her to her eye the smaller one is the larger now and the larger, left on the console, can fit into the smaller. Leela comments "that's silly." He tells her it is transdimensional engineering, a key Time Lord discovery. The TARDIS arrives somewhere, Leela hoping it is somewhere exciting. They look out the scanner, shutters opening up and down. They see a metal wall. Leela asks him if he knows where they are -- and when he doesn't, she laughs, "You don't know where we are? You mean you can't control this machine?" He answers: 9 times out of 10, 7 out of 10, maybe 5 out of 10. She picks up a rifle-ray-gun weapon from the Tesh but he tells her she won't need it, also explaining that "If people see you mean them no harm...they never try to hurt you, 9 times out of 10."

Zilda is on tracking and finds left and right tracking are fine. V58 is overseeing the Sandminer. Poul goes to find a missing Chub. Uvanov and Zilda quibble over Chub. Uvanov thinks all the Founding Families -- Chub being one of the 28, Zilda and Cass being from two others -- all stick together and that is sickening. Toos reports they have found tifan, lucanol, and other minerals. Uvanov smiles, "Cheer up, Zilda, I'll make you rich again." She makes a face.

In the storage room, Chub wonders in the name of the seven suns where his robot is to help him move and launch an instrument package before the hatches are locked. It comes at him, calmly talking to him, but its eyes glow red, and it comes at him to kill him. In the hallway, Poul hears Chub scream.

V32, on the control room deck, tells them an obstruction is on the forward scoop deck... none knowing this is the TARDIS.

The Doctor and Leela look around the scoop deck area and see hard alloy, formed under great pressure. They also see vents to the outside desert.

The robots are ordered to remove the TARDIS and a large crane comes down from above and closes around the TARDIS top and hauls it up and away. Borj, from another area, calls and tells Uvanov that more power is coming. They switch to the motor units. Poul arrives on the command deck and reports that Chub is dead, strangled, murdered. Uvanov won't lose this sandstorm and claims they can't do anything for Chub now -- this storm means money for all of them.

The Doctor and Leela are at a vent, closer now. The Doctor thinks this is a desert unless the tide has gone out. To Leela who sees no trees, no water, this is new and beautiful. To the Doctor it is a bit garish for his taste. A sandstorm rises with sand approaching at 1000 miles an hour. It can cut them to pieces. They run but find the TARDIS gone, Leela commenting she heard something before -- the TARDIS being taken away. The Doctor leads her back to the vents, hoping that there is some manual way to close the vents but upon their arrival back, the vents are closed by someone else. Leela thinks someone must have overheard.

Poul takes the Commander to the storage room where Chub was killed and they find a red marker, a disk shape, in his hand. Uvanov claims they should never have let him on board. Uvanov doesn't like scientists.

In the scoop area, Leela looks up, "I do not think I like this metal world." Robots arrive and stare the Doctor in the face.

Uvanov addresses the crew in a conference room. One, Carrel, is on his way. This is a tour year tour the crew is on and someone could have killed Chub if Chub got on their nerves enough during that time. Dask identifies the red marker as a corpse marker used to identify deactivated robots when the technicians at the construction center has to turn all their robots off at the same time and send them to reconstruction. Techs named the robot deactivation disks corpse markers as a joke; Poul wondering about their sense of humor. Cass interupts Zilda but they stick together against Uvanov. Zilda claims Chub's scream could have been a recording... if he was strangled, how could he have let out a scream? The crew start blaming each other for killing Chub. Borg joking, puts a marker on Cass's arm.

The Doctor and Leela are brought to a large lounge type of area with comfortable couches, which the Doctor deduces are for humans, not robots. Robots do not need to sit down. Leela deduces that the robots don't feel and calls them "creepy mechanical men." She looks at minerals on a table -- large crystal like objects. At the door, one of the robots listens to their conversation. The Doctor once saw a Sandminer of this type on the planet Calma Beta and explains how they work to Leela. Leela looks at him, not really getting it all, "Sometimes you talk like a Tech." The Doctor, absent mindedly, says, "Thank you." Leela counters, "It was not well meant." SV7 comes in and will report them to the Commander and leaves. Even though he told them to remain here, the Doctor uses the sonic screwdriver to open the door. Leela takes out her knife as they move out into the hallway.

Uvanov is told about the intruders and he thinks they killed Chub but Borg disagrees. The robots begin mining. Uvanov orders the crew back to work but they sit there and won't go. Dask agrees that they should get back to work. SV7 calls -- the prisoners have escaped.

In the hall, the Doctor eats a jellybaby. Leela senses something and ducks into a storage room where she finds the covered body of Chub, under a sheet.

The Doctor buys himself some time by taking out a pipe and breathing through it from below the sand.

Leela hides as robots D64 and V9 take Chub's body out of the storage room; she follows them. Cass, Poul, and Borg go to search for the Doctor and Leela against Uvanov's orders -- the crew is not armed. Toos thinks they should all search and Dask comments that the robots can handle it. SV21 gets the Doctor out of the holding stack -- the gauge registered the Doctor as an impurity in the ore. The dead man is Karrel.

The Controller Robot makes SV21 grab the Doctor to take him back to a secure area.

Leela rushes back to the lounge area and does not find the Doctor. She sees curtains moving and sneaks up on them. Behind the curtain, she finds Cass dead. A robot, D-84 comes at her, grabs her and turns her around, covering her mouth. He tells Leela it is important he not be found here and tells her he won't kill her. He did not kill Carr. The two talk to each other as if they are becoming friendly but when Uvanov enters, D84 grabs Leela again. He finds Cass's body and slaps Leela who responds by kicking him between the legs. If he tries it again, she will cripple him. The D robots, they are not supposed to talk. Leela asks if anyone has asked D84 that. Uvanov shouts at her that he could have her executed on the spot but she counters with the fact that he couldn't since he must have some reason to think she is not guilty. Poul enters and checks Cass. "You must be stronger than you look," he says to Leela. Leela laughs, "And you must be stupider than you look if you think I killed him." Poul suggests Dask could be the killer even though he brought up the name of the red markers as corpse markers. Poul also tells Uvanov this is perhaps a double bluff, something the commander doesn't seem to have heard of. Uvanov orders the robot to bring Leela, who insists she did not kill him.

In the conference room, the Doctor eats jellybabies from a bag of them. When he offers Borg some, Borg yells at him to shut up and smacks the bag, scattering jelly babies on the floor. Leela is brought in and tells him she had to restrain Uvanov who is set on murder. The Doctor tells her the crew are frightened, thus dangerous because they are frightened. The Doctor meets Uvanov, telling him they are travellers here by accident. Uvanov fails to believe this since they are 100 million miles square into the desert. The Doctor thinks Uvanov asked a rhetorical question but tries to answer the Commander's interrogation. Uvanov thinks the Doctor might be using the double bluff. They ask the Doctor what is more suspicious than a stowaway. The Doctor answers, "Oh, a dead stowaway." The real killer meant for the Doctor to die in the holding tube. The crew continues to suspect each other as well as the Doctor and Leela. The Doctor starts to tell them there is another possibility. When Borg won't listen to reason, the Doctor tells him, "You know, you're a classic example of the inverse ratio between the size of the mouth and the size of the brain." Borg starts choking the Doctor but Leela hits Borg in the stomach. The robots take Leela and the Doctor out.

The Commander asks Zilda why she hates him so much. She tells him that he flatters himself. He thought the idea of her getting money would please her but tells her when he gets back from this trip, he will be richer than she.

In a hallway, a human hand gives a red marker to a robot, who says, "I will kill Zilda."

The Doctor and Leela are strapped in by robots who bend the metallic straps like butter -- when unlocked the molecules are soft. Their arms are left free. Leela asks the Doctor what he is doing when she sees him closing his eyes and raising his fingers and hands to his head. He tells her he is concentrating to get through a million combinations to his lock. It should take two or three weeks. Leela comments he is not taking this very seriously. He gets very, very serious and tells her he is, "I have a feeling if the murderer doesn't kill us, the commander will, assuming they're not one and the same person."

On the control room deck, Toos reports they are 50% under. Zilda, on deck for only an hour, declares it is her break time, much to Uvanov's displeasure. Dask tells him they could all use some rest time. V9 and V16, on consoles, report they are at ground center 720. Uvanov declares he has never lost an ore stream yet.

Poul visits the Doctor and Leela in the detention room, telling them he would like to help them. Leela has noted, "He is not what he seems. He moves like a hunter and watches all the time." Poul asks the Doctor what he thinks is happening. The Doctor coughs -- a sign for Poul to let him loose. Poul does and the Doctor tells him one of the robots could have done it even though the robots have a prime directive not to kill. The Doctor suggests someone could bypass it. Poul tells him that is impossible but the Doctor responds that bumble bee flight is aerodynamically impossible. The Doctor leads Poul out. Leela coughs to alert Poul into letting her out of her bonds as well. He does and she thanks him.

Zilda makes her way into Uvanov's room and goes through his files.

Poul, Leela, and the Doctor go to the storage room where Chub was found dead. Chub, Poul tells them, was a meterologist from the government. Chub was sending up weather balloons. The Doctor reenacts the circumstances leading up to Chub's death and makes Poul realize a robot could have killed Chub.

Zilda, in Commander Uvanov's room, cries and calls the control room, yelling that Uvanov did it and he is a liar. She is hysterical. She blames him for something -- which everyone thinks is the murders. Uvanov leaves the deck, running for his quarters.

Poul takes the Doctor and Leela back to the lounge area. The Doctor tells him this is not the only "robot dependant" civilization in the galaxy. The Doctor makes Leela sit down and tells her about the vicious circle of robot unease leading to more dependance on robots leading back to more unease. If robots have gone haywire and are killing, the Doctor quite casually tells Leela, this will be the end of this civilization.

Uvanov finds Zilda dead in his room. Poul arrives and finds him standing over her. Uvanov thought when he was as rich as Zilda, the girl would like him. He sounds as if he loved her and comments he must be going soft. Poul thinks Uvanov killed her and relieves him of command. When Uvanov resists, Poul hits the man down and tells one of the robots to watch over him.

In the lounge room, Leela feels something wrong, not just what has happened up to now but something different. Something that can destroy them all. She asks the Doctor if he can feel it. He snaps that he cannot and neither can she, while also quoting "something wicked this way comes..."

The Sandminer hits a rough spot and the motors jam due to sabotage. The vehicle tilts and everyone is thrown off their feet. The Doctor lands near a chair and picks his head up, "Please, don't say I told you so."

Dask went down to try to unjam the motors. Talking over the radio, Toos tells Poul, who tells her to try to hold the vehicle steady. She calls to him, "Oh thanks, I would never have thought of that."

SV7 is with Uvanov.

As the units start to hit overload, the Doctor and Leela run into the control room, he asking if he can help, defending that he and Leela had nothing to do with this sabotage. As the power sounds out louder and louder, Toos yells that it is funny how they are always around whenever anything bad happens. The Doctor yells so he can be heard, "It's a gift!" If they cut the power, the Sandminer will sink; if not, it will explode. Dask calls from the engines -- he reports that Borg has been strangled to death. The drive links have been sabotaged. He will need a Delta repair kit. D14 reports they cannot cut the controls. The power continues to go critical.

The Doctor convinces Dask into cutting both zeta link cables, which causes the motive units to shut down, and make the Sandminer sink. The Doctor comments on Dask's calmness, telling him this isn't the Titanic, even though he respects a calm man. They figure a way to refloat the Sandminer. Dask tells the Doctor to stay in the control deck and help repair the remote control units while he goes down to the engines alone. Leela comments on the air; Toos tells her the refrig refiltering system has shut down. Leela notices Toos has been injured and begins to treat her. She bandages Toos's hand and tells her a saying of her tribe, "If you're bleeding, look for an injured man."

Poul finds Toos and explains that ten years ago, Uvanov left a man outside his Miner to die because Uvanov wouldn't be distracted from his money making drilling. Toos doesn't believe it at first but Poul admits he and Karrel were both there. The man left outside was Zilda's brother. The hull pressure increases but Dask calls -- he's repaired the damaged motor units. The Sandminer moves and lifts out of the dirt; life support with only superficial damage. Whispering, the Doctor calls on Leela to stay with Poul who is lying about something and knows more than he is telling. Inoperative robots are taken to security storage. There are strict rules about robot disposal. Poul is aggravated at this -- there are more rules for robots than for humans. Leela notices the water has no taste. Poul tells her the water has been through the filtration system eight times by now. Leela asks why Poul does it, why he lives so strange a life. He supposes money... he hasn't been on a mission like this in four years. He prefers living with people than robots. He leaves the crew room and locks Leela in.

Dask is in the robot repair shop where a robot with a crushed head is. He puts a red marker on it and leaves just as Poul comes in. Poul sees blood on one of the hands of the robots and this starts him into a nervous breakdown of some type.

SV7 reports to a small room where a face on a screen uses voice commands to alter SV7's programming to second communication channel. This person also gives the robot further orders. The robot's eyes glow red as it accepts the orders. The voice tells SV7, "Go brother, you are one of us now."

In the lounge area, D84 examines Zilda's body, surprised when the Doctor opens the curtain to reveal himself. The Doctor lets D84 know that he is aware he can talk, is not like the other robots on board (not a Voc, Super Voc, or a real Dum). To get D84 to talk to him, the Doctor threatens to tell SV7 that this Dum can talk. D84 and the Doctor discuss their situation.

A masked man in a workshop uses a descending Laseron probe on a robot. The probe enters the robot's brain and alters its circuits, causing a program violation. This being gives his "brother" a new life, a new freedom... free to kill.

D84 confirms the Doctor's guessing about him. D84 is indeed a spy for the mining company. The company took the threats of robot revolution seriously. These threats came in the form of letters which were signed by Taren Capel, an important scientist whose face has never been seen by the company or D84. There are no records of what he looks like. He worked on robots and his entire childhood was spent living with only robots, practically being raised by them. The Doctor lets D84 realize that Capel could have substituted himself for one of the crew before this mission departed. D84 has downcast in his voice when he says, "I've failed." The Doctor asks D84 if he would like to come with him and he agrees. The pair go in search of Capel's workshop... he must have one aboard... he can't go working on brains in the hallway.

SV7 enters Toos's quarters, menacingly, but doesn't attack her. She asks it to bring Leela to her since her hand is hurting again. SV7 tells her Uvanov is free, having used his voice command to get away from his confinement in his quarters. It also tells her there are some main power system failures which will affect the lights and the doors in the form of malfunctions. SV7 does not obey Toos. It goes to the workshop.

In the hallway, robots do not heed Leela's call to let her out. They go about their own business... which might be killing. In the hall, D84 hears Leela but the Doctor does not seem to. D84 accidentally scares the Doctor by sneaking up behind him. D84 tries to tell the Doctor that he heard a cry. The Doctor keeps telling him that it was his startled yelp, not realizing it was Leela. D84 keeps repeating that he heard a cry over and over as he follows the Doctor through the halls.

In the workshop, SV7 gives out red markers. One is given to V6 who takes it, "I will kill Toos." Another is given to V4 to kill the Doctor and another is given to V5 who will go to kill Leela, all having very calm voices as they pronounce they will kill their given targets.

In the crew room, Leela is trying her knife on the door when the lights go out. The door opens suddenly and V5 steps in and attacks her. She throws her knife but th robot just removes it and tosses it aside. She avoids the robots and throws a blanket over its face. She manages to get out of the room.

The Doctor and D84 find the small workshop and the Laseron probe machine and table. D84 finds a communicator that can be used by a human or a robot. Since he is not supposed to have a real voice, D84 tells the Doctor to call the others. The Doctor warns Toos and tells her to head for the command deck. She is unconvinced at first but then accepts his assessment of the situation. As she starts to leave, V6 blocks the hallway. She closes the door and catches the hand of the robot in it. The robot removes its arm from the wrist of the hand. It continues to threaten her from outside, telling her a door is not a barrier. Toos calls the Doctor back for help. D84 will go -- he is faster and stronger than the Doctor.

Leela hides in the robot repair room and finds Poul hiding, insane and afraid of robots. He yells at her and calls robots "the walking dead", telling her the robots are really in control of the people. When she tries to help him leave, he calls for the robots to get Leela here -- the robots want her, not him. She leaves him alone, telling him he can stay here but he must be quiet.

Uvanov grabs a probe from a rack and sticks it into V5's head, stopping it. The lights go dim and Uvanov checks the robot but it hits him in a last effort.

Toos's door opens and V6 enters the room to kill her.

The Doctor carries the semi conscious Uvanov in the hallway. They see SV7 but instead of helping them, it orders another robot to kill them. The Doctor puts Uvanov down, out of the way. He puts a hat on V4 and it battles the hurt robot that was following the Doctor and Uvanov (V5). This gives the two men a time to escape. Toos is unconsious on her bed. V6 is about to finish her off but he is called away by Dask and leaves. When Leela arrives she finds D84 standing over Toos so picks up the closest thing to her... the earlier fallen hand of V6. D84 ask politely her to not throw hands at him. Toos is alive. D84 is told about Poul by Leela, so the robot leaves to go collect Poul to the Control Deck.

Leela and Toos make their way there as well but have to hide in one of the hopper rooms when V5 and V6 return to the area. They do not search the hopper since V35 through V40 searched the hoppers already. The two robots head for the storage bays. Toos calls the Doctor on her radio but SV7 answers and asks who she is. He tells her to stay where she is and she tells him she is in her quarters. Leela stops her from telling him where they really are hiding. Something didn't feel right to her. Toos realizes SV7 should know her immediately via her voice codes in his programming -- he shouldn't have asked her who she was. Leela thinks that it was not SV7.

The Doctor and Uvanov arrive on the Command Deck where they find the friendly robots frozen... deactivated. Someone hit the robot deactivation control. The two women come to the Command Deck where Uvanov hugs Toos. Uvanov thinks all the robots are deactivated now and all they have to do is send up a satellite distress beacon and they will be brought back to base. The Doctor tells him to look as D84 carries Poul in. The Doctor tells Uvanov that he reminds him of a woman called Marie-Antionette -- he is not believing there is revolution going on. Dask, Taren Capel, controls the robots except for D84 who is controlled by Poul, both Poul and D84 working for the Company. Poul's body language is all wrong. Leela reminds the Doctor she told him that Poul moved like a hunter. Poul has robophobia which Uvanov saw in a young kid once. This kid ran out of the Sandminer before Uvanov could stop him and died. This was Zilda's brother. Zilda's father had it all hushed up so that no one would think the boy was a coward -- which he wasn't. He had this syndrome, -- Grimwade's Syndrome -- an irrational fear of robots. SV7 calls them and tells them if they surrender, they will die quickly rather than slowly. The Doctor realizes the 7 or 9 electron blasting packs can be converted into Anti-Robot bombs by magnetizing the packs. The Doctor can't be everywhere at once, thus Toos and Uvanov will prepare the packs. The Doctor takes Leela and D84 with him. He tells Toos not to open the door to anyone and that if he and his two friends fail, it is up to Toos and Uvanov to warn the outside world.

Leela, the Doctor, and D84 hide as ten robots pass by.

Dask bangs on the control room door, yelling that the robots are coming and Toos and Uvanov should let him in. Toos stops Uvanov from opening the door. The robots could have him hostage and could be forcing him to make them open the door. Dask is in fact, ordering the robots to force the doors open. He is in a robot silver outfit and his face is green and silver.

Leela, the Doctor, and D84 make it to the Robot Mortuary. D84 is sent to the storage room to get one of Chub's canisters -- a canister of helium gas. Leela sees the same blood on a robot's hand that Poul saw. The Doctor thinks the blood is Borg's and that Borg probably put up a fight. Leela asks what robophobia is. Robots have no body language, no eye contact, no posture or personal space, almost like walking, talking dead men. This results in paranoia and personality disintergration in some humans who are around the robots so often. The Doctor explains as he taps into Dask's private circuit -- Dask is Taren Capel.

In the Command Deck, Uvanov and Toos work, realizing they are decoys when just then, the robots banging at the door, stop.

In the Robot Mortuary deactivation room, Leela guesses that Dask turned off the friendly mechanical men; the Doctor tells her later Dask will convert them to his mode in order for them to be able to kill. D84 arrives with the gas. He wants to go with the Doctor even though the Doctor tells him to stay here. The final deactivation device that the Doctor has fashioned from a communicator, if used, could destroy D84's brain as well as all the other robots. D84 says, "I am not important." The Doctor thinks however he is very important and ask him to stay here. D84 tells him it is his duty to the Company to go. The Doctor allows him to come.

In the Command Deck, Poul is up but sees a robot outlined at another side of the room near a thin part of the wall. This is V5. Poul begs forgiveness from the robots. Dask orders V5 to enter and V5 tells the three, "All humans have to die." Uvanov puts a blast pack on the wall and blows V5 up. V5 enters but falls. Uvanov thinks it is time for them to go on the offensive, "The Doctor is going to need some help."

In the hall, when V5 won't respond, Dask claims he is going to release more of the robot's brothers from bondage and then they will be irresistable. He takes one robot with him.

The Doctor, D84, and Leela move into Dask's workshop. The Doctor hands D84 the deactivation device, "Hold this and don't press anything." He ushers Leela into a small closet on the floor and hands her the gas cylinder, telling her to open the valve slowly but only when Dask comes in. When she asks why, he tells her the helium mixed with air will alter the resonance of the larynx.

Dask enters and pushes a probe into D84's head. A robot hits the Doctor as he rushes to helpl D84. It moves him against the wall. Leela begins releasing the gas. Dask orders the robot to put the Doctor on the bench.

Toos and Uvanov hide behind a large painting in the hall, glad robots have no appreciation for art or imagination. They avoid SV7. The pair follow him.

In the workshop, Dask is glad the Doctor has come to -- and the Doctor is strapped down to a horizontal table with a manacle attached to either side of his head. He will make the Doctor suffer for almost ruining his plans -- he is going to burn out the Doctor's brain. A probe is slowly lowering toward the Doctor's head from the device on and above his head and attached to the table ending.

While Dask and the Doctor verbally spar, D84 is slowly crawling to the fallen robot deactivator. Dask's voice is slowly changing due to the helium in the air and this will make his voice unrecognizable; thus they will not obey him.

The Doctor tells Dask he looks ridiculous in that outfit, "Not half the robot your father was." Dask turns up the power on the probe, losing his calm, which the Doctor tells him is not the robot way; also telling him without humans there would be no robots.

D84 reaches and activates the robot destroyer and says, "Goodbye, my friend." His head and the heads of any other robots in the room all explode.