Benny is shot down while flying over the abandoned colony on the remote planet Jegg-Sau, and she awakens after the crash to find that she’s being tended to by a mineralogist named Ethan Kalwell and his childlike teenage daughter, Elise. Elise apologises for accidentally shooting down Benny’s shuttle with a rocket launcher that she’d mistaken for a distress flare; she and her father have been stranded here for a year, ever since their shuttle crashed, killing Ethan’s brother. Now it seems Benny too is stuck here with Ethan, Elise, and their Robot, a clunky ancient prototype labelled K-103 that states it has been designed to replace the human being in a variety of dangerous tasks. As Benny recovers from the shock of the crash, however, she realises that there’s something suspicious about Ethan’s story; why drag his only daughter out to the edge of human space just to look for minerals, and why has nobody come in search of them since they went missing?
(Later, while being interrogated by the Robot, Benny admits that she too had ulterior motives for coming to Jegg-Sau. One of the colonists, Robert Eliot Whitman, supposedly stole several priceless art treasures from his former employers on Earth with the intention of selling them to fund the colony; however, cheap terraforming ruined the planet’s soil, and the colonists were forced to abandon the planet and leave the treasures behind. Whitman died without ever returning for the treasures, and Braxiatel sent Benny here to have a look around for them. As evidence that they still exist, Benny reveals that the Robot itself is one of the missing art treasures.)
Benny takes the Robot back to the remains of her shuttle to see whether it can be repaired, while Ethan and Elise continue their mineralogical survey. Benny has been in trouble so often that Braxiatel has built an extra power pack into her distress beacon, so she’s confident that someone will pick out the signal even from this far out. However, moments after activating the beacon, she is confronted by a native animal like a cross between a jackal and a hyena, and the Robot smashes the beacon beyond repair while defending Benny from the animal. Benny, though frustrated, concedes that the Robot was trying to save her life; all she can do now is hope that someone was monitoring her and detected the signal before it cut out. In the meantime, the Robot takes the animal’s carcass back to the dome to cook it for Benny’s dinner. Elise is distressed to see the dead animal; she is acting in a manner much younger than her years, but Benny assumes that her odd behaviour is due to her isolation on this remote planet. Even so, she’s surprised and unnerved when Elise innocently asks whether the Robot smashed the distress beacon on purpose.
Elise gives Benny a tour of the former colony dome, claiming that she didn’t like the planet at first but now loves living here. Benny is surprised to see that there are plenty of food rations in the dome, but all expired; the dome also contains a damaged radio that occasionally receives signals but is unable to transmit. However, she is most interested in the hastily concealed doorway in the hillside, especially when Elise claims that the Robot does not permit her to go inside. Benny reminds Elise that the Robot is just a tool that is supposed to obey her instructions, not vice versa, and approaches the doorway -- but the Robot unexpectedly blocks the entrance, much to her surprise, as she’d thought it was cooking on the other side of the dome. Ethan finds them and explains that he’s ordered the Robot to protect this door, which leads to a storehouse full of relics that the colonists left behind. When Benny inquires about these relics, Ethan and Elise take her back to the dome for “gloating time,” and show her a glass case containing several priceless artefacts, including a Wyndham Lewis painting, a 15th-century samurai sword, and Egyptian bowls from the 3rd century BC. Ethan insists that the relics are his for gloating over, as any ordinary person would, and Benny, frustrated by his bland selfishness, reminds him that her friends will soon be arriving to put an end to Ethan and Elise’s solitude. To her surprise, however, the Kalwells refuse to leave, insisting that they must finish their survey -- even though these relics could make them wealthier than any mineral ore.
The Robot once again pops up unexpectedly to inform Benny that it has finished cooking her dinner. Ethan tries sending Benny off to eat on her own, claiming that he and Elise are fully satisfied with the expired rations; however, Elise has recalled eating one of these animals when she first landed, and tells her father that she’d like to try doing so again. Nevertheless, perhaps because of Benny’s earlier outburst, Ethan and Elise sit some distance away from the fire, and she can barely make them out as they sit and chew their food. Disturbed by their odd behaviour, and upset that Ethan seems to have brainwashed his daughter into accepting this barren life, Benny decides to continue with her own mission. That night, she distracts the Robot and tries to slip into the shelter to see the other relics for herself, but the Robot unexpectedly looms up ahead of her and sends her away. Benny leaves, frustrated, unable to understand how the Robot managed to circle around and get ahead of her -- and because she believes at this point that Ethan and Elise brought the Robot to Jegg-Sau with them, she fails to see the obvious answer.
The next morning, Benny examines Kalwell’s survey results for herself, and finds that there is no mineral ore worth exploiting on the planet; Ethan and Elise have just been continuing the surveys to keep themselves occupied. Benny tries to convince Elise that it would be better for her to leave this isolated planet and see the wonders and beauty in the rest of the Universe, but Elise insists that this planet is the best place there is to live. Benny gives up on her and returns to her shuttle, only to find the Robot working there. It orders her to return to the dome, and she refuses, reminding it that it’s supposed to be the one who obeys orders. However, although it claims that it’s programmed to preserve human life, she can’t help but notice that it is now advancing upon her in a threatening manner, claiming that she is a disruptive element and must be corrected. Benny retreats into the remains of her shuttle, and the Robot chases her inside; however, Kalwell unexpectedly appears through a gap in the damaged hull and ushers Benny out to safety. Moments later, the shuttle explodes behind her, and Kalwell explains that he finished work on the bomb that the Robot had been installing when Benny interrupted it. Benny realises that the Robot was setting a trap to kill her friends when they came to rescue her. She also realises that Kalwell is behaving quite differently, and she learns why when he reveals that he’s never met her before; the Ethan and Elise at the dome are in fact two lifelike humanoid robots.
A safe distance away from the burning shuttle, Kalwell explains that he, his brother and Elise came to Jegg-Sau specifically in search of the Robot, only to find four of them here. Kalwell is a historian and part-time writer who’d found out that one of his ancestors, a man named Kettlewell, had built the prototype Robots from which nanotechnology and other advanced technologies had been derived. The first Robot went badly wrong, and Kettlewell’s work was suppressed during the subsequent cover-up; however, it eventually fell into the hands of the corporations, who used it to develop inventions that by all rights should have made Kalwell’s family rich. Hoping to restore his ancestor’s reputation and prove his claim to some of the subsequent patents, Kalwell traced one of the antique Robot prototypes to Jegg-Sau, where it had been taken by Whitman; however, rather than preserving the Robot as an antique, it turns out the colonists activated it and used it to build a workforce of similar Robots. This is why there is no mineral wealth on the planet any longer; the Robots mined it all out for their own foundry. But the Robots’ CPUs are modelled on human neural pathways, and they are constructed of a unique alloy of living metal; they are practically human in many ways, and when the colonists abandoned them here, the Robots became confused and lonely. When Kalwell’s shuttle crashed, killing his brother and stranding him and Elise here, the Robots assumed that the colonists had returned to put everything right again, and thus nursed them back to health in a VR suite. However, when Ethan and Elise did not behave as the Robots had expected, the Robots decided that the newcomers were acting disruptively, and used their programmed knowledge of battlefield medicine to “correct” them. Kalwell escaped, but he could hear Elise screaming as the Robots altered her and built a replacement for him...
Four Robots approach Benny and Kalwell’s hiding place, presumably investigating the explosion. Benny tries to lure them away from the real Kalwell, but they capture her and take her to the hillside shelter for behavioural analysis. There, they force her to relive her experiences on Jegg-Sau, while monitoring and analysing her reactions in order to create a more lifelike replica. She lashes out at them, furious that they’ve killed the real Elise just because a bunch of failed farmers bailed out and left them alone; the Robots may claim that they’re improving her, but that’s just because they have no idea how real humans interact. The Robots disagree, and show her the VR suite in which the real Ethan and Elise recuperated after their crash; according to their records, Whitman spent a lot of time in here, interacting with the AI constructs. However, Benny recognises the VR environment as a soft-core porn package of a pick-up bar, and explains that Whitman just used it to escape from the complexities of real life for short periods of time. The Robot questioning her is forced to concede that Whitman did not appear happy even when he used this program, and that it has been interacting with Benny in a complex and potentially rewarding manner during their interrogation. Benny promises not to be disruptive if the Robot will leave her unimproved, and the Robot agrees to try interacting with a real, complicated human being for a while to see what will happen.
The Robots thus return Benny to the dome, where she puts on a happy face and agrees to celebrate her return with the robot Ethan and Elise. As she’d hoped, they decide to celebrate with more gloating time, and Benny suggests that they make this an extra-special celebration by taking the artefacts out of the case to touch them rather than just looking. Elise isn’t sure that this is a good idea, but Benny successfully convinces Ethan to open up the case and take out the samurai sword to admire its craftsmanship. He does so, and after gloating over his treasure, he offers it to Benny. Bracing herself to do what she must, Benny takes the sword and swings it at Ethan, destroying his robot body and smashing open the cabinet. But to Benny’s horror, the broken glass sticks in Elise’s flesh and eyes, and she begins bleeding profusely. Bewildered and horrified, Benny flees from the dome as the furious Elise, accusing Benny of killing her father, gives chase without waiting for the Robots to repair her damaged flesh interface.
As the Robots close in on Benny, rescue ships arrive from the interstellar Red Cross, and Benny rushes to her shuttle, as the rescue ships will probably be homing in on the location of her distress call. However, a gigantic Robot is standing in the remains of the shuttle; this is the Robot that planted the bomb, and instead of being destroyed in the explosion, the living metal of which it is constructed absorbed the energy and used it to grow. Benny is reunited with the other Kalwell, and as she lashes out at him for misleading her about Elise’s nature, the damaged replica Elise arrives, bleeding profusely and running down. She runs into Kalwell’s arms when she hears him speak, and Benny, wracked with guilt, can do nothing but watch as the childlike Elise dies, unable to understand what’s happening to her.
The giant Robot then stirs to life and attacks the approaching Red Cross jets -- and Kalwell, whom Benny had assumed to be in a state of shock, suddenly joins the other Robots as they prepare to defend themselves. He too is a humanoid robot, a more advanced version whose behaviour is modelled more closely to the original Ethan Kalwell’s; he was allowed to roam free by the Robots in order to keep his mind occupied, just as the other Ethan was allowed to conduct the pointless mineralogical surveys, but now that they face a threat they need his help to repel the intruders and keep the colony safe for when the colonists return. Benny tries vainly to convince them that the colonists are never coming back and that this conflict is pointless, but the Robots insist that they will create a new colony using their humanoid replicas. The Robots were designed to replace humans in a variety of dangerous tasks -- and, driven mad by their isolation, they have concluded that simply being alive is the most dangerous task of all and that they must replace any humans who behave poorly or illogically.
The Robots drain the energy out of the robot Kalwell and Elise’s bodies and convert it to mass, growing to giant size and attacking the Red Cross jets. Realising that the Robots are hopelessly mad, Benny flees back to the shelter, hoping to find the relics she came for in the first place. Unfortunately, she finds that the priceless treasures are all damp, stained and corroded, as the Robots had no idea how to go about preserving them properly. Sickened, Benny rushes back to the dome, where she tries to contact the jets via the radio she found earlier and get them to call off their attack; the Robots are now the only survivors of this colony and of the relics that were stored here, and if the jets destroy them, all of this horror will have been for nothing. But the radio itself is a relic, capable only of receiving and not transmitting, and Benny’s desperate pleas are lost in static as the jets barrel in on their attack run...