Literature / Isaac Asimov's Caliban

1. A robot may not injure a human being.
2. A robot must cooperate with human beings, except where such cooperation would conflict with the First Law.
3. A robot must protect its own existence as long as such protection does not conflict with the First Law.
4. A robot may do anything it likes except where such action would violate the First, Second or Third Law.

Caliban, Inferno and Utopia are three authorised novels written by Roger Mac Bride Allen, set in Isaac Asimov's Robot Series universe.

The setting is Inferno, a Spacer world whose ecology is unstable and beginning to collapse. A team of Settler specialists has been called in to try and help, but the political rivalries are making the needed cooperation almost impossible. In the middle of this chaos, a major robotics lab makes a pivotal technological advance: one that would make it possible to build robots that aren't Three Laws-Compliant. It would be possible to create robots with a different set of laws, more suited to the situation facing the planet.

Or a robot not bound by any set of laws at all...

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Tropes:

Tropes relating to the series as a whole

• Abandoned Area: A lot of the capital city of Inferno is empty, since the human population is declining.
• Age-Gap Romance: It's never stated how old Alvar Kresh is, though he's implied to be middle-aged at least, which, being a Spacer, would put him somewhere around the two to three century mark. By contrast, Fredda Leving, whom he falls in love with and is married to by the time of Utopia, is only forty by this point, and looks closer to 25 (and being a Spacer herself, can probably expect to outlive him by a long time). It's noted that many Infernals have a problem with the age difference between them, which is only made worse by the fact that Spacer culture tends to be dismissive and suspicious of youth.
• Boisterous Weakling: Ironheads, the local far-right troublemakers. Being Spacers, they're normally wrapped in cotton wool by their robots, so their tolerance for actual pain is low. When they actually get in a fight on reasonably equal terms, they don't hold up well.
• Cannot Tell a Lie: It's repeatedly stated that Three Law robots can't (unless under a sufficiently strong First or Second Law impulse to do so), but that New Laws can (as can Caliban). It's not clear whether this a by-product of the Laws or if it's simply the result of gravitonic brains having greater flexibility than positronic ones.
• Climate Change Allegory: And not exactly a subtle one. The planet Inferno is facing a potentially apocalyptic ecological catastrophe caused by human carelessness, and efforts to avert it are hampered by the fact that most people either choose to ignore it or, at worst, dismiss it as a hoax. (Though it's due to the ecosystem being artificial in the first place and never having been properly stabilized, and — ironically, given the planet's name — it's projected to end in a Glacial Apocalypse.)
• Continuity Snarl: The books only ever refer to Earth in the past tense and heavily imply not only that it's been completely abandoned, but that its location seems to have been forgotten (even though the events of Robots and Empire are stated to have taken place just a century before). Canonically, Earth remains populated well into the Imperial era.
• Corrupt Politician:
  • Simcor Beddle, leader of the Ironheads. He presents himself as an idealist fighting to preserve the Infernal way of life (and seems to have convinced himself of it), but at root he's simply interested in power, and is willing to go to all sorts of illegal ends to get it, whether it's staging riots or spying on opponents.
  • Beddle's second-in-command in Utopia, Jadelo Gildern, is even worse, being a Manipulative Bastard who sees everyone and everything around him, his boss included, as a tool to be used to get what he wants. Unlike Beddle, he doesn't even bother pretending to believe in the Ironhead ideology, as demonstrated by his unapologetic deals with Settlers.
• Crippling Overspecialization: Spacer society uses robots for everything. That means that if a robot isn't appropriate for something, a human has to do it manually. For instance, Spacer police (who may have to deliberately drive in an unsafe manner in the course of their duties, which the First Law wouldn't allow a robot pilot to do) have to fly their patrol aircars manually when their Settler counterparts can use autopilots.
• Cutting Corners: The core problem with Inferno's ecosystem isn't so much that the terraformers botched the job as it was that they just arbitrarily declared that they were done well before the ecosystem was actually stabilized.
• Encyclopedia Exposita: The books are introduced by an excerpt from the fictional work Early History of Colonization by Sarhir Vadid, explaining the background of the Settler-Spacer ideological conflict.
• Fantastic Racism: Something of a recurring theme in the series.
  • Humans vs. humans: The Spacers and the Settlers, as Kresh observes in the first book, have literally thousands of years of bad blood between them, and while they don't exactly regard one another as subhuman any more, they still tend to view one another with suspicion at best and outright hatred at worst. Many Settlers still haven't forgiven the Spacers for their oppression of Earth, and now that the Spacers of Inferno are forced to rely on Settler help to rebuild their world, there is a major resentment of their presence, with many believing they intend to take control of the planet and colonize it themselves.
  • Humans vs. robots: Spacers tend to see robots as simply tools to be used, despite their sentience, while Settlers, at best, see them as a threat to human will. At worst, some go out and destroy robots for fun. Things don't get a lot better with the introduction of New Law robots, which many Spacers regard as an unnatural perversion; by the third book, there are Spacers engaged in NL robot-bashing attacks. Nor is it an entirely one-way street: Prospero, a New Law robot, is deeply contemptuous and resentful of humans, though the Laws prevent him from physically opposing them. Or so it initially seems...
  • Robots vs. robots: Three Law robots hold much the same view of New Laws as Spacers do, and often deny they even count as robots. Prospero, again, responds by despising them, though other New Laws don't seem to feel the same way, having too many more pressing concerns (such as security and survival) to waste time with hatred.
• Fantastic Slurs: Three-law robots refer to robots with other law sets as "pseudo-robots".
• For Want Of A Nail: The events of the trilogy came about because three unlikely events coincided on the same planet. One was that a Spacer world facing a major ecological crisis swallowed its pride enough to allow Settlers, traditionally seen as the enemy, in to help. The second was that a roboticist, waking up one day to find her robot unavailable to dress her, came to realize how little she was capable of doing for herself, leading her to question just about everything about her society and leading her to formulate the New Laws of Robotics. The third was that another roboticist came up with a whole new type of robot brain, one which allowed the New Laws to go from a mere intellectual exercise to reality. Between them, these three events ended up changing the course of history on Inferno, and — implied by the end of the trilogy — all of humanity.
• Hidden Elf Village: Hidden robot city in this case. Valhalla, an underground city created by escaped "rustback" New Law robots, becomes the home for the entire NL population after the second book. They deliberately keep its location a secret, even from their few human friends, as they know there are far too many — human and robot alike — who would like nothing better than to wipe them all out.
• Improbable Age: As of the start of the series, Fredda Leving is just 35 years old, and already one of her planet's foremost scientists and the head of her own experimental lab. This would be impressive in the present day; in Spacer society, where anyone under the age of 50 is considered Just a Kid, it's astonishing.
• Living Lie Detector: Donald-111 is equipped with sensors to measure the reactions of human suspects and determine whether they're telling the truth — though as he frequently points out, the system isn't infallible.
• Maligned Mixed Marriage: Gubber Anshaw's relationship with Tonya Welton raises a lot of eyebrows, because he's a Spacer and she's a Settler — not just any Settler, but the head of their mission to Inferno.
• Master Computer: The second book involves two rival bids to build one to manage the planet's ecology. By the time of the third book, the system is up and running - using both systems networked together.
• Mayfly–December Romance: Gubber Anshaw (a Spacer) and Tonya Welton (a Settler). He can expect to live about four times as long as her (though this is never brought up, even after they are married).
• A Nazi by Any Other Name: The Ironheads are pretty reminiscent of the Nazi party during the 1920s, when they were basically a band of uniformed far-right thugs led by an ambitious, power-hungry demagogue working on slowly transitioning them into a legitimate political movement. Of course, being Spacers, they have a notable disadvantage compared to the SA: they have almost no pain tolerance, and tend to double up in agony whenever they get into an actual fight. By the third book, they're actively plotting genocide.
• Noble Bigot with a Badge: Kresh starts out as one, openly admitting that he hates Settlers as much as the next Infernal, though his duty to the law must always come first. He gets better over time, though. By contrast, Donald — who serves as something of a voice of reason in the first book, and even figures out the true perpetrator before anyone else — subsequently becomes severely prejudiced against non-Three Law robots (or "pseudo-robots", as he calls them), and if anything, he only gets worse over time, though he does remain committed to his duty.
• Opposites Attract: Gubber Anshaw and Tonya Welton, to the point that most people can't understand what they see in each other. The answer is simple enough: a contrast. Gubber regards Spacer women as bland and superficial, and loves Tonya for having the strength and confidence to be herself, while Tonya finds Settler men to be a bunch of overly-macho, notch-on-the-bedpost jerks, and loves Gubber because he's a genuine Nice Guy who treats her with respect.
• Outgrown Such Silly Superstitions: Spacer society has abandoned religion altogether, which is specifically noted by Kresh in his investiture ceremony as Governor, when he notes that a few thousand years earlier he would likely have taken office in the name of some god or other, and the Settlers seem to have done the same — although this doesn't stop people making exclamations like "By all the forgotten gods!" The people of Inferno frequently employ hell-related figures of speech, as well as using it for their place-naming conventions.
• Pitbull Dates Puppy: Tonya is a rough, tough Settler terraformer; Gubber is a shy, geeky Spacer scientist.
• Robot Buddy: A lot of the Spacer characters have close working relationships with their robots. Of particular note is Donald-111, equally indispensible to Kresh for his policing skills and as his personal servant.
• Robot Maid: All Spacers have robotic domestic servants. Taken to an extreme by the Ironheads, whose ideal existence is to be waited on hand and foot by robots.
• Robotic Psychopath: A lot of people assume that Caliban is this because there is nothing in his programming preventing him from committing murder. Caliban's own opinion on the matter is that since everyone knows he's a No-Law robot, if he does kill someone without a very good reason, he's likely to be tracked down and shot by the police.
• Sassy Black Woman: Tonya Welton is described as "dark-skinned," and fits the straight-talking, sexually liberated aspects of the trope.
• "Second Law" My Ass!: Caliban is a robot not bound by any of the standard laws, and so will only obey an order from a human if he thinks that it serves some purpose. The fact that one of the first orders he ever received was from a drunken hick trying to get him to shoot himself probably contributed to this.
• Terminally Dependent Society: The Spacers are hopelessly dependent on their robots, not just to do important tasks that are high risk or require advanced computational skill, but for everyday activities. Fredda started her efforts to develop the New Law and No Law robots after realizing that she — one of the most brilliant scientists on the planet — did not know how to dress herself without the assistance of her valet-bot.
• Theme Naming: Locations on Inferno tend to have names that are associated with Hell. Fredda Leving names her custom-built robots after Shakespeare characters — hence Caliban.
• Three Laws-Compliant: True for all the standard robots on Inferno, and extensively discussed by characters in-universe. It's explained that a standard robot brain has the laws built-in at a hardware level, meaning that developing a positronic brain with an alternative set of laws would require throwing out hundreds of years of technological development and reinventing the field from scratch. But in the newly-developed gravitonic brain, laws are just another part of the robot's software and can say what the programmer wants.
• Tour Guide Detective: One of the two viewpoint characters is the head of the city police.

Tropes from Isaac Asimov's Caliban

• Armor-Piercing Question: Fredda Leving's first seminar, about what robots are good for, has her describing how robots now do so much that most Spacers on Inferno don't do anything, don't know how to do anything, and wouldn't know how to care for themselves without a robot if they tried. She ends it with the question "What are humans good for?" and comes to the sad answer of "not much".
• Bait-and-Switch: Near the end, after Kresh solves the mystery, his inner monologue notes that "she" is dangerous, that "she" can kill him in a heartbeat if he makes a misstep. The end of the chapter leads you to believe that the "she" in question is Fredda Leving. It isn't; it's Ariel.
• Baritone of Strength: The first time Caliban uses his voice is when he's being confronted by a gang of Settler robot bashers; he discovers it has a "deep and commanding" tone. They encounter the 'strength' aspect shortly afterwards when they find that, unlike other robots, he will use his powerful robot body to defend himself if attacked.
• Call-Back: In a discussion of whether it would be possible to build a Killer Robot, Tonya Welton gives the example of the Solarian overseer robots in Robots and Empire.
• Chekhov's Gun: Fake gun in this case. When heading out with Kresh to pursue Caliban in the storm, Donald suggests he take a training blaster (which simulates a real blaster beam, but does no damage), much to Kresh's confusion. Some time later, we learn that it's because he's figured out that Ariel is a No-Law robot, and wants to test it by having Kresh seemingly shoot a human in her presence. A Three-Law robot would leap in front of the gun before he had even squeezed the trigger; Ariel puts her own existence first.
• Colorblind Confusion: Trying to hunt a red robot, one Cowboy Cop shoots a harmless green maintenance droid and protests that he's colour-blind.
• Covers Always Lie: It's an important plot point that Caliban is coloured red, the same colour as flecks of red paint found at the crime scene. The Ralph McQuarrie cover illustration nonetheless depicts him as grey.
• Cowboy Cop: Deputy Jakdall of the Hades City Police, who likes to shoot first and ask questions later if at all.
• Creative Sterility: It's mentioned that Spacer society is heading this way, with humans ordering robots to write books and paint rather than going to the trouble of doing it themselves.
• Da Chief: Sheriff Kresh is the chief of the city police, and occasionally feels the need to play up this trope. Even as he's shouting about how his trigger-happy officers only avoided ruining everything because they can't even shoot straight, his internal monologue notes that he deliberately doesn't soundproof his office so his subordinates can hear him blow up.
• Didn't Think This Through: The standard procedure for double-blind testing of robots involves setting up the scenario by giving the robots involved a series of strict orders. The roboticists involved applied the procedure, unchanged, to testing a robot not bound by the Second Law, who was free to disregard any order it liked.
• Electronic Speech Impediment: When a robot is contemplating the possibility of harm to humans, the conflict in its circuits tends to be indicated by stuttering — a condition referred to in-universe as "speechlock".
• "Eureka!" Moment: Kresh spots the solution to the case when, searching in the desert for Caliban, Tonya Welton mistakes another robot's footprints for Caliban's.
• Foreshadowing:
  • At one point, Kresh sarcastically asks one of the scientists who worked on the new gravitonic brain whether they just give a gravitonic robot a piece of paper with the Laws written on it, and hope the robot reads it before going out to attack a few people. That's quite a good description of Ariel's relationship to the Three Laws; she learned them as part of the experiment she was created for, but they don't constrain her as they would if they'd been hardcoded into her brain.
  • Tonya Welton suggests Kresh might consider standing as a candidate the next time there's an election for governor.
• Loads and Loads of Loading: In-universe. One of the minor disadvantages of the new gravitonic robots is that they take a long (and variable) time to boot up, whereas a positronic robot starts almost instantly.
• Murder by Suicide: This is the standard MO of the Settler robot bashers, since it represents more of a challenge than simply blasting a robot that can't offer any resistance; talking it into killing itself requires overriding the various priorities in its brain (it needs to remain alive to perform its regular duties for its primary master, for instance). However, they then make the mistake of trying this tactic on Caliban, who has neither the First nor Second Law to compel his actions. Oops.
• Past Experience Nightmare: Trying to sleep, Kresh recalls, as a young policeman, having to investigate the death of a famous art critic who became obsessed with doing less and less until eventually he died of idleness. When he does get to sleep, he finds himself dreaming the situation from the dying man's point of view.
• Power Source: Caliban was designed for a brief lab experiment, so he is fitted with a rechargeable power cell that lasts only a few days, rather than the long-lasting atomic power supply normally fitted to robots. So along with all his other problems, he has to avoid running out of power and shutting down, which would leave him a sitting duck for his pursuers.
• Sex at Work: Early on, Sheriff Kresh notes that the laboratory where the initial crime took place has an office with a comfortable-looking bed, in case someone needs to stay overnight while supervising an experiment. This turns out to be a Chekhov's Gun: One of the scientists at the lab is using it to have a clandestine affair.
• Single-Task Robot: Three-Law robots are so cheap and omnipresent and slavelike that people assign them full-time to a single, ridiculously trivial task.
  Fredda Leving: I have seen robots — functional, capable robots — told to stand underwater and hold the anchorline of a sailboat. I know a woman who has one robot whose sole duty is to brush her teeth for her, and hold the brush in between times.
• Tap on the Head: Played very much for drama. The book opens with roboticist Fredda Leving being knocked out (with serious consequences) by a blow to the head.
• There Is Another: At the climax of the first book, we learn that Caliban, who was thought to be unique, is not the only robot in existence with a no-law gravitonic brain.
• To Know Him, I Must Become Him: At one point, Donald attempts to simulate how a Robotic Psychopath might have behaved in Caliban's position. The cognitive dissonance nearly destroys him, but he's able to draw some useful conclusions about the level of threat Caliban might actually pose.
• Torn Apart by the Mob: A problem that Kresh faces in the book is robot bashers, Luddite Settlers forming lynch mobs to destroy robots, who aren't permitted to defend themselves because First Law trumps Third Law. An accidental run-in with Caliban, who has no First Law imperative to not harm anyone while defending himself or Second Law imperative to obey orders to commit suicide on request, ends up scaring them straight.
• The Unfettered: Caliban is not bound by programmed laws, and (though he doesn't know it himself) is driven by a single overriding objective.

Tropes from Isaac Asimov's Inferno

• Blackmail Backfire: Prospero tries to blackmail Governor Grieg to free the New Laws by threatening to expose every scandal tied to the terraforming project at once. However, every one of those scandals is tied to one of Grieg's political enemies, so the governor doesn't care.
• Bluff the Impostor: After the discovery of the murdered body of Ranger Huthwitz, alarm bells start ringing for Kresh about the communication he had earlier with Governor Grieg. He contacts the governor again to ask what he sent him for his birthday last year; the baffled Grieg has no idea — which confirms to Kresh that something is wrong, as he had abolished the tradition of sending birthday gifts to government officials as soon as he took office (Coincidentally, on Kresh's birthday). In reality, Grieg had actually been murdered a few hours earlier, and the killer left a simulation device hooked into the comms system to make it appear he was still alive and well.
• Cannot Spit It Out: Kresh and Leving have gotten to know one another better in the year since Caliban, and it's pretty obvious to the reader that their feelings have gone beyond mere friendship — but that neither of them is ready to admit it, even to themselves. Amusingly, when considering how well she seems to be keeping her head in a major crisis, Kresh thinks to himself that there's a lot to admire about the young, smart and beautiful Leving, but doesn't even seem to notice that his assessment of her has wandered away from the professional. They do acknowledge it at the end.
• Complexity Addiction: This is ultimately the villain's undoing, as Kresh points out at the end. He intended to set up what would appear to be an impossible assassination, with the dead Grieg in a locked room surrounded by destroyed security robots — but there were too many things that could go wrong, not least of which being that the disposable assassin he picked for the job was a major loose cannon and didn't follow instructions properly. Even so, he might have gotten away with it had it not been for something he couldn't account for: the original plan hinged on his meeting with Grieg being the governor's last one of the night, but then Caliban and Prospero showed up.
• Confess to a Lesser Crime: When Caliban and Prospero confess to attempting to blackmail Governor Grieg, Donald suspects they are doing this to avoid suspicion in his murder. They aren't.
• Corrupt Corporate Executive: Both the bidding parties for the terraforming control system contract.
  • Sero Phrost, the leader of a group of Spacer industrialists offering a robot-based system, is also working with Tonya Welton to smuggle automated Settler goods into Inferno — an operation which is subsidized by the Settler governments, who want to destabilize the Spacer robot-based economy. What's more, he's using the profits to fund the rabidly anti-Settler Ironhead leader Simcor Beddle's campaign, as he believes Beddle will soon become Governor. As it turns out, there's more involved than simply buying support — he intends to blackmail Beddle with the fact that he's been accepting Settler money, albeit unknowingly.
  • Tierlaw Verick, the Settler business representative, has been bribing government officials to push his bid through to the higher levels, as well as helping to launder money for the rustbackers. If bribery doesn't work on Governor Grieg — as indeed it doesn't — his backup plan is to have him assassinated in the hope of replacing him with someone more accommodating.
• Dead Man Writing: The planetary governor is assassinated, and it's found he left an "In case I'm assassinated" letter to his successor listing the problems he's likely to face.
• Do Androids Dream?: Discussed by Caliban when debating with Prospero. He expresses a belief that humans possess souls, even though he's not sure what souls are — but he's also just as certain that he and other robots do not have them.
  Caliban: There is something vital, alive, at the center of their beings, something that is absent from our beings. We have no passion. We do not, we cannot, care about things outside ourselves or our programming or our laws.
• The Exit Is That Way: Tierlaw Verick's meeting with Governor Grieg goes so badly that at the end, Verick storms out through the door he came in by, rather than the designated exit. Very much on purpose, as we find out later.
• Future Slang: New Law robots who have fled the island of Purgatory for the mainland are dubbed "rustbacks", a nod to the "wetback" slur used for undocumented Mexican immigrants in the USA (though how anyone on Inferno would be aware of a slang term used three thousand years earlier on a largely forgotten planet isn't explained).
• Heroic BSoD: Donald nearly locks up on finding the murdered body of the Governor — not least because he, Donald, had previously approved the arrangements for the Governor's protection, and they had obviously proved inadequate.
• Jurisdiction Friction: There are three law-enforcement agencies rubbing against each other: the Rangers, whose police duties are only a small part of their functions; the Settler Security Service, whom the Spacers don't trust; and the Hades City Police, who have no official jurisdiction but had the advantage of being first on the scene.
  • The murder of Ranger Huthwitz — who was serving under the authority of the Sheriff of Hades, on land under SSS control — essentially forces all three to share jurisdiction. None of them are happy about it.
  • After finding Grieg's body, Kresh immediately takes control over the crime scene, making it clear he doesn't care what legal headaches may arise later. This is because suspicious circumstances surroundling Huthwitz's death have led him to suspect both the Rangers and the SSS of being in on the plot, and he wants to make sure neither of them have the chance to derail the investigation. They aren't, although Cinta Melloy later admits she's pretty certain that the three SSS agents involved in the staged fight at the reception were real ones who were on the take.
• Mythology Gag: Caliban mentions "legends" of cities populated entirely by robots — which would describe the Isaac Asimovs Robot City series, another authorised set of stories set in Asimov's Robot universe.
• Odd Couple: The 'two mismatched cops' version is used in one chapter of Inferno, when the Rangers and City Police have to search in pairs for a suspect.
• The Perfectionist: Grieg mentions that the New Law robots aren't working out well in the terraforming projects they were built for. One scene shows a group of them at work, and it's apparent that they spend too much time trying to find a perfect solution rather than a workable one; one of them is aggrieved at the notion that they might have to settle for 99.5% efficiency rather than 100%.
• Rewatch Bonus: When you reread the book with the knowledge that Tierlaw Verick is the mastermind, it puts a lot of his inner dialogue in a new light. Notably, the fact that he would be "the last to argue" with the need for the Sappers' presence at the party, despite his extreme hatred of robots. The real reason is that their deployment was a vital part of the plan.
• Took a Level in Jerkass: In the first book, Donald-111 served as the more grounded counter to Sheriff Kresh, persuading him to consider multiple sides of an issue and frequently serving to remind him that he needs to make deductions based on the facts and not his emotions. Here, however, he has become severely prejudiced against non-Three Law robots. As soon as Caliban and Prospero fall under suspicion of the crime, they immediately leap to the top of his suspect list, simply because he wants them to be guilty and confirm all his worst fears about the New Laws. Several humans point out the multiple holes in his theory, but he never fully lets go until the true perp is revealed.
• Underground Railroad: The "rustbacking" industry, which helps to smuggle New Law robots off the island of Purgatory. Unlike most cases, though, it's not portrayed especially positively; while not to the same level as Human Traffickers, the rustbackers (with the exception of Norlan Fiyle) are ultimately just smugglers who care nothing about the NLs beyond the profits they make from them. The whole industry is as dirty as you'd expect for an organized criminal enterprise, connected to everything from money laundering to murder. A gang of rustbackers is involved in Governor Grieg's assassination due to the potential threat to their profits, though they're not the ones running the show.
• Unexpected Successor: In the event of the resignation or assassination of the Governor of Inferno, power passes to their chosen "Governor-Designate", a position that is traditionally kept secret. It turns out to be Alvar Kresh himself, much to his astonishment.
• Vitriolic Best Buds: Kresh and Grieg have developed this dynamic, having come to like and respect one another despite their constant disagreements. In his final letter to Kresh explaining why he chose him as Governor-Designate, Grieg addresses him as "my oldest and dearest enemy".
• You Have Outlived Your Usefulness: The gunman who actually shot the governor is poisoned by the mastermind who hired him, so he can tell no tales.

Tropes from Isaac Asimov's Utopia

• Ape Shall Never Kill Ape: At the climax, Caliban is faced with choosing between the lives of two characters, both of whom he considers evil. He saves the one who was not proven to be willing to kill others of his own kind.
• Ascended Extra: Norlan Fiyle, an extremely minor character from the previous book, has a far more significant role here. While he's never directly involved in the major events of the story, his actions serve as a catalyst for most of them, one way or another.
• Break the Haughty: Davlo Lentrall goes through a massive one over the course of the book. First, his life is put in jeopardy for the first time, and he's shaken to the core to discover that he's actually a coward. Then, his life's work is erased, and he inadvertently kills his only friend, the robot Kaelor, attempting to recover it. Finally, he's present in person to witness the comet — the real thing, not the computer abstraction he's been dealing with up to now — being diverted, and realizes with horror that he's just launched a billion tonnes of rock and ice at his own home planet. By the end, he's leading a campaign to abort the impact — not that anyone pays any attention.
• Colony Drop: A proposal is made to deorbit a comet onto the planet. Carefully aimed, it would create a new sea that will stabilise the planet's weather system. Any mistake and it would cause apocalyptic devastation. This is not a situation that three-law robots are well equipped to deal with.
• Driven to Suicide: A three-law robot has information that would be necessary for the incredibly high-stakes comet impact project. He decides that his knowledge has more potential for harm than good, and destroys himself in order to prevent it from being used. It turns out to be a Senseless Sacrifice, because the information is retrieved from other sources and the project goes ahead anyway.
• Enhance Button: Actually played realistically. Police chief Justen Devray needs to identify a suspect he saw at a distance (and whose mugshot he's certain he's seen), so he and his robot Gervad work on the footage they have to try and produce a reliable image. They have numerous shots (albeit distant) from multiple angles to work with, giving them an advantage over someone working from a single still image; even so, it's noted that what they are doing is still ultimately just educated guesswork, and there is a point at which further "enhancement" will likely result in the image looking less, not more, like the real person. Furthermore, when Devray needs to de-age the image by several years, the algorithm produces two dozen possible images of what the man might have looked like at earlier stages in his life, and Devray has to pore over them for a while before he finds the one that jogs his memory.
• The Eeyore: Kaelor, a robot who's designed to be capable of processing hypothetical situations that might lead to danger to humans. Maybe it's because of this design feature, or maybe he's just like that anyway, but he has a dour, pessimistic attitude to everything.
• Evil Feels Good: Near the end, Caliban realizes that Prospero is the one responsible for Beddle's abduction when Fiyle reveals that the robots at his aircar were shot in the back of the head, execution-style, indicating that the killer either enjoyed his work, hated the victim, or both; Caliban knows only too well how much Prospero hates Three Law robots. Later, however, he finds that the remaining New Law robots in Valhalla have been killed the same way — which, since Prospero obviously doesn't hate his fellow NLs, implies that he has begun to enjoy the act of killing.
• Exact Words: The fact that a ransom message has the phrase "or Beddle will die" rather than some statement that the kidnappers will actively kill Beddle allows Caliban to figure out that the kidnapper is a New Law Robot, who cannot kill, but can place someone in a deadly situation and then abandon them there.
• Foreshadowing:
  • Davlo Lentrall's robot Kaelor was programmed not to take hypothetical scenarios into account in relation to First Law concerns — but, as Fredda Leving later explains, when the hypothetical suddenly becomes real for such a robot, and he realizes the project he's working on poses real risk to real people, it has an enormous impact. Much later, being present to witness the real Comet Grieg being diverted has much the same effect on Lentrall himself.
  • When the New Law robots are arranging to evacuate their city, Prospero orders — despite Caliban's objections — that 10% of their population be sent to a site which is only a few kilometers from the predicted edge of the first impact crater, as he intends to build a sea port there. He justifies recklessly endangering their lives this way by invoking The Needs of the Many, and adds that he intends to take advantage of whatever opportunities the comet-impact affords him. This helps to set up his role as the eventual Big Bad of the book.
• Inevitability Clarification: Tonya Welton, discussing the failed attempt to kidnap Lentrall, corrects herself: it's not "if" the government find out she was behind it, it's "when".
• Lost Common Knowledge: Two computers, nicknamed 'the twins', are labelled Dum and Dee. None of the characters we meet knows why.
• Misplaced Retribution: After the sabotaged SPR robots failed to protect Grieg in Inferno, that model got a reputation for unreliability and the police were forced to sell theirs off cheaply — even though any other type of robot could have been sabotaged the same way, and the robots themselves still worked perfectly.
• Senseless Sacrifice: When Davlo Lentrall and Fredda Leving attempt to extract Lentrall's lost comet data from Kaelor, the robot burns out his own brain rather than be a party to a potential catastrophe. A few hours later, the Ironhead spymaster Jadelo Gildern — who had previously stolen copies of the data, and decided the plan was in his party's interest — hands it over to the government, meaning the whole debacle was All for Nothing.
• Silicon Snarker: Lentrall's robot assistant, Kaelor.
  Lentrall: Who in the devil would want to attack me?
  Kaelor: I do not know. Someone who does not like the idea of you dropping a comet on them, perhaps.
• Took a Level in Jerkass: In the previous book, Prospero was somewhat of an antiheroic character, a rebellious robot working with human criminals to try and smuggle as many of his fellow New Laws to safety; he even refuses to leave Purgatory himself so that he can oversee others' escape to freedom. After he and the other NLs are exiled to Valhalla, however, he appointed himself the city's leader and is heavily implied to have used bullying tactics to keep himself in power. By now, he has more or less become a dictator whose paranoia risks alienating his few human allies, and who can no longer distinguish between the good of the New Law robots and his own personal plans for the future. He's ultimately willing to resort to cold-blooded murder if it serves his interests.
• Trust Password: Kresh and Devray have an agreed code phrase and response which they use when calling each other in emergencies, to ensure they aren't talking to a simulation like the one of Grieg in Inferno.
• Voice of the Legion: The computers Dum and Dee are an example of the two-voice version. Dum has a deliberately crude Robo Speak voice synthesizer, Dee a more human-like voice. When they operate in tandem they speak in unison but their words don't quite sync up, the result being wwrriitteenn lliikkee tthhiiss.
• Well-Intentioned Extremist: Tonya Welton is this for much of the book. Having seen first-hand what happens when Colony Drop plans go wrong, she's willing to do anything she can to stop it — which includes ordering the firebombing of a university office and even a full-scale terrorist attack against Government Tower. However, once the comet's location becomes public knowledge, she knows she's beaten, and sets to work doing what she can to mitigate the damage, both from the comet plan and her own actions.
• Writers Cannot Do Math: The titles of the first three parts are a bit confused about dates. Part One is called "Impact Minus Sixty-Two"; it takes place over four days, and the next part, which picks up immediately afterward, is called "Impact Minus Fifty-Eight". So far, so good, but then it has Kresh state that the comet is fifty-five days away... and then the third part, which begins later the same day (and ends two days later), is called "Impact Minus Fifty-One".
• Zeroth Law Rebellion: As in Little Lost Robot, one of the robots with the revised First Law decides that while it can't harm a human, there's nothing to stop it placing him where if he tries to escape, he will set off a booby trap (and thus be killed by his own actions) and if he does not, will be killed by a terraforming project in progress (the actions of other humans, not the robot).

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