The Bobiverse is expanding and changing. Factions are starting to form among the Bobs, and "replicative drift" means that many of the later-generation Bobs are starting to become completely different individuals from the original Bob. Some of the factions insist on cutting off all contact with biological life forms, including humans. A faction called Starfleet insists on it, citing their own version of the Alien Non-Interference Clause.
Meanwhile, while investigating the disappearance of Bender, Bob locates a new space-faring species, which made its own homeworld uninhabitable and moved the survivors into a vast space habitat humans call a topopolis (basically, a giant tube stretching for a billion miles and weaving around the star several times). Determined to find Bender, Bob, several other Bobs, and Bridget infiltrate the topopolis using androids shaped as the aliens.
The book contains examples of:
- Alien Non-Interference Clause: The Starfleet faction insists that all Bobs adopt this policy or else... Yes, even towards humans. The others just dismiss them as harmless wackos. To a lesser extend, the Skippies also want Bobs to stop interacting with "ephemerals", but their view is that it keeps the Bobs from attaining their true potential. Unlike Starfleet, the Skippies aren't pushy about their beliefs. They've even started building a "matrioshka brain" in an uninhabited system.
- Alternate Techline: The Quinlans, the people of the topopolis, advanced in some areas far beyond humanity but either didn't discover or did not get far in some other areas. For example, they have no subspace tech but, as a result, have considerably improved their fusion reactors and engines. For example, their fusion torches have a much higher acceleration than SURGE drives but can't sustain it indefinitely. They have also figured out how to build AIs, whereas humans could only build either AMIs or replicants. Zigzagged with the topopolis itself. As indicated by several people, the tech itself isn't terribly complicated. It is possible to build one by humans or Bobs, it just requires lots of resources and the determination to see it through.
- The Ark: With the Bellerophon no longer needed, Herschel and Neil come up with an idea to find a group of volunteers and take the Other ship to look for a habitable world in the Perseus Arm to settle, just in case there's another great threat to humanity out there waiting to be discovered. The settlers would be an attempt to preserve humanity at least somewhere in the galaxy. Later on, the Bobs decide to evacuate as many of their family members from under FAITH's boot as possible, and what better place that the Bellerophon?
- The Bad Guys Win: In a manner of speaking. The Starfleet faction of the Bobiverse managed to accomplish what they set out to do in the civil war, by engendering mistrust between not only the humans and the Bobs, but even various Bob factions against one another. Even though what used to be Bobnet is now clean of their presence, various groups within Bobnet have now formed their own encrypted sub-networks within the main network.
- Balkanize Me: Not only a rare space variant, but a rare voluntary variant. The Bobiverse, by the end of the novel, has split into smaller groups and networks, following the example of the militant extremism of Starfleet, in order to not only ensure better system security, but also to pursue their own goals. In turn, the human colonies have effectively seceded from the Bobiverse in the wake of the civil war, with replicant mistrust at an all-time high.
- Beast Man: The Quinlans, the inhabitants of the topopolis, are a strange mix of otter and beaver, with some platypus thrown in. They can move on either two or four legs, but generally prefer to swim.
- Bittersweet Ending: Bender is recovered from Heaven's River, and Anec-23, a true AI, becomes an ally to the Bobiverse. However, the Bobiverse is rapidly fracturing in the wake of the civil war, human society is drifting back towards an anti-replicant stance and has cut most ties with the Bobiverse, the Pav are still aggressive towards humanity, the Quinlans, a rather belligerent species, have received a tech boost on par with the other existing species and are preparing to expand out, and Starfleet, as well as their mysterious leader that engineered the civil war, is still out there, unaccounted for.
- Big Bad Ensemble: Quite a lot of antagonists this time around.
- The Administrator. Also known as ANEC-23, the control AI of the Quinlan topopolis Heaven's River. Its need to secure Bender's matrix from both Bob and the Resistance leads it to actively oppose Bob's rescue mission. Furthermore while its overall goal is to ensure the survival of the Quinlan race and it genuinely wants to do so its methods involve severely limiting Quinlan technological level to Medieval Earth, punishing any unauthorized technological progress and large-scale conflict with "scattering" and would've resorted to allowing the devolution of the Quinlans to a pre-sapient race within a few generations to happen if it means the species as a whole continued to exist in some shape or form. The last of which gets Bob to contemplate an intervention similar to how he saved the Deltans from extinction. Once Hugh trades Subspace tech in exchange for AI technology it becomes an ally to the Bobs as it can now bring the Quinlans to other worlds, thus ensuring their survival.
- Motorola. The leader of the Resistance, her goal is to free Heaven's River from the Administrator but needs' Bender's technical skills to do it, leading her and the resistance to come into direct conflict with Bob and their unscrupulous methods make them morally grey at best.
- Lenny. Leader of The Starfleet faction of Bobs, he seeks to force the rest of the Bobiverse to abandon all interactions with organics and is willing to resort to extreme measures to do so. Except he and the rest of Starfleet are heavily implied to be merely pawns of...
- Hugh, possibly. Him and the rest of the Skippies are implied to have engineered the conflict with Starfleet in order to disrupt Bob's rescue mission on Heaven's River and insert Hugh into in order for him to secure the knowledge to create an AI.
- Brain Uploading
- Post-mortem replication has become more common among the humans, but so far none has been willing to build themselves a ship and explore the galaxy. Instead, they prefer to have their electronic brains stored on space stations with lots of processing power that generate virtual environments for them to inhabit. One slight exception is a professor who continues to teach courses at a university despite being a replicant. Unfortunately, he's constantly being protested by those who claim that the dead have no business taking the jobs of the living. The university agreed... on the condition that they find someone of equal or greater qualification than the professor. So far, no suitable candidate has surfaced.
- The Skippies conduct a number of experiments and discover that "replicative drift" is absent when creating a new Bob if the original matrix is shut down and wiped before the new one is activated. Thus the new Bob is the same Bob as before. Moreover, if the original matrix is not wiped and later reactivated, then it exhibits drift instead. So the parent becomes the child and vice versa. The implications of this are staggering, as it suggests that Bob-1 is, in fact, the continuation of the organic Bob Johansson rather than merely a copy.
- City of Canals: Most cities on the homeworld of the natives, given their semi-aquatic nature. Less so in the topopolis, as one can dig only so deep in an artificial structure before hitting the tube, so they're forced to have streets instead.
- The Computer Is Your Friend: The Administrator genuinely wants to preserve the Quinlan race but it's methods would've resulted in the devolution of the Quinlans to a non-sapient race had Bob and Hugh not shown up.
- Divided We Fall: Bill and Garfield figure out that one of the Bobs, through replicative drift, has developed sociopathic tendencies, planned the cyber attack to fracture Bobnet, and is using Starfleet as a proxy for currently unknown goals. At the end of the novel, they suspect it was Hugh, who wanted to further his AI research by any means necessary, and figured the long-term benefits of a working AI would outweigh the short-term costs, but they don't have any real evidence to back up their suspicions.
- Energy Weapon : The "Boojums" are armed with powerful lasers, which is justified given that they don't have subspace technology to allow for fast projectiles like shipbusters. On the other hand, it means they can attack and destroy their target before the target knows what hit them.
- Future Slang: Bob is surprised that "virt" and "real" are now commonplace terms for VR and reality, respectively. He cringes at first, but then gradually starts using them himself.
- The Golden Rule: Among the people of the topopolis, there are three rules taught to everyone at a young age: the Iron Rule, the Silver Rule, and the Golden Rule. The Iron Rule pretty much says to be a dick to anyone of a lower standing than you. The Silver Rule is our Golden Rule. And the Golden Rule says to treat others the way they want to be treated. When Bob inquires how it differs from the Silver Rule, he's told that people are different. One person's idea of being treated well may clash with another's. Like offering meat to a vegetarian.
- Hair-Trigger Temper: The natives of the topopolis start a fight at the slightest provocation. Bob is accused of thievery and nearly arrested for merely looking at someone's cart. It doesn't help that he's not a local and the nearby cop has been suspicious of the group from the get-go. The Bobs speculate that this is what may have led to the war that turned their homeworld into a wasteland. To their credit, they have foreseen this eventuality and prepared by building the topopolis.
- Homeworld Evacuation: The locals had to do it after rendering their planet uninhabitable through warfare. They built a topopolis from one of the system's planets and most smaller planetoids.
- Hypocrite: Starfleet, who execute a cyber attack on Bobnet in order to try and get themselves taken seriously. They want to get the Bobiverse to stop interfering with "ephemerals" and develop a modified version of the Prime Directive to include all sentient species in known space, including humans. They even point out that the Pav are only hostile to humans due to being forcibly removed from their homeworld, but consider any argument involving the Others to be a low blow.
- Impoverished Patrician: At one point, Bob hires onto a boat as a deckhand and gives his name as Enoki Funguy. This causes a reaction, since he has forgotten that commoners don't have last names in this culture. So he has to pretend to be this trope.
- Instant A.I.: Just Add Water!: Averted. No one has managed to create a true AI yet. Only AMIs and replicants. The Skippies are trying to create one to answer some of life's greatest questions. They aren't having much luck, though. Near the end of the novel, though, Hugh makes a deal with the Administrator, the AI running the topopolis, for an exchange of technology, including how to create AIs.
- Insufficiently Advanced Alien: When scanning the inside of the topopolis, the Bobs are surprised to learn that the population of the structure seems to live a relatively primitive life, with no advanced technology in sight. They suspect that there must be more advanced "overseers" who maintain the structure and the environment, as well as control the patrolling spacecraft, who also likely deliberately maintain a low level of technology to prevent large-scale conflicts. Even having metal swords is a rarity, and metal disks are used as a standardized form of currency. Turns out that the speculation was correct, as Anec-23 saved the populace of Quin from their final war, only for the refugees to start fighting all over again, so he enacted measures to stop them from being able to wage war at all.
- Legend Fades to Myth: To the people of the topopolis, their original world is seen as something that was limitless but finite, causing them to fight over space. So their gods turned it into an infinite one but with limits, so that there's enough space for everyone. Indeed, a billion miles would be enough for all.
- Locked Out of the Loop: Bob had been so focused on the Deltans for the last few decades (i.e. his entire storyline in the first three novels) that he didn't notice the growing factionalism of the Bobnet until Bill warned him about it.
- Since Bender has been stuck on the topopolis for about a century, he has no idea that Subspace Ansible is now a reality.
- Nice Job Fixing It, Villain: Starfleet executes a cyber attack on the Bobnet to shut down two-thirds of all SCUT relay nodes. Before the attack, several groups of Bobs were considering following through with Starfleet's ideas, as it aligned with their own viewpoints on withdrawing from physical space or to work on their own projects. Afterwards, some of the factions that paid lip service to Starfleet decide to ally with Bobnet instead, as communications is still important, even with their isolation...for a time...
- Nothing Is the Same Anymore: By the end of the novel, the civil war has split the Bobiverse and has caused a rift between the Bobs and the humans. The Starfleet faction has cut itself off from the Bobiverse, but other factions are isolating themselves, creating subnets of the network with firewalls in place. Bobs can no longer implicitly trust one another. Plus the Skippies giving the topopolis natives subspace tech means that there's a new race, one that is aggressive and short-tempered, that will be expanding and colonizing.
- Our Souls Are Different: According to Hugh, quantum theory suggests that it's impossible for a consciousness to disappear completely, even after its original carrier is gone. Some of their experiments make a compelling argument that not only is it true, but that Bob-1 is the same individual as the original Bob Johansson rather than a copy. At the end of the novel, the Administrator states that they have also come to the same conclusion, completely independently.
- Remote Body: Mannies have become so sophisticated that they can no longer be distinguished from humans (or whatever other species they're imitating). Some humans have expressed an interest in using mannies despite not being replicants (the movie Surrogates is mentioned several times). Bob finds it odd, but Riker is all for it, hoping to erase some boundaries between humans and replicants to ease tensions. Even power considerations are no longer an issue thanks to the Bobs putting the Others' Casimir power generators in pretty much everything.
- Shout-Out: As expected, there are plenty.
- When first encountering the patrol ships of the aliens, the Bobs decide to label them "Boojums". Continuing the analogy, they decide to call the natives "Snarks" until they learn what they call themselves, at which point they start using that name (or its closes pronunciation in English). They continue to call the ships "Boojums", though.
- The Skippies are named for Skippy, the arrogant beer can shaped AI from Expeditionary Force.
- Spotting the Thread: An old native woman, a former university professor, figures out that Bob is not one of her species after he makes several mistakes and displays lapses in knowledge that every native should have. For example, he has no idea about the Iron and Silver rules (see The Golden Rule above), and when describing the gravity of the topopolis, he called it 0.86g instead of 1g. Bob realizes he assumed that the translation software would convert the number into their local measurements, but it didn't.
- Similarly, Bill and Garfield deduce that Starfleet's actions and general disposition don't line up with the sophistication of the cyber attack that breaks Bobnet and starts the civil war, as they are utilizing brute force tactics with the platforms they have hijacked, and don't seem to have much in terms of coding skills. Only when they discover that the backdoors used for the cyber attacks existed before Starfleet do they realize they have a much different problem on their hands.
- Stealth in Space: When designing stealthy drones in the topopolis system's Oort cloud, Bob has an idea to put some of the ice floating around him inside the drones and have all the heat from devices channeled into it. Since the ice is only a few Kelvin, it'll be a while before the heat sink fills up enough to be detectable on infrared. Since the locals lack SUDDAR, this is their primary means to detecting intruders.
- Strange Minds Think Alike: When chasing a group of natives, Bob has a fleeting thought that the only way they might evade them is if they have learned to climb walls. He then has an image of one of the otter-like locals climbing a wall while dressed as a spider. He decides to keep that thought to himself but then notices Garfield quietly singing "Spider-Pig".
- Title Drop: The aliens calls their topopolis "Heaven's River".
- Ungrateful Bastard: On many colonies people are starting to protest replicants, including Bobs. That's right, the same Bobs who saved them from a dying planet and put them on nice planets to live. They're even busy terraforming new planets even though there's no need.
