The setting is a distant future (at least 1500 years from now), where humanity has settled 47 star systems thanks to a hyperspace-like field called the Flow that can be used to traverse enormous interstellar distances in a matter of weeks or months. All populated systems are united into an empire called the Interdependency (technically, the Holy Empire of the Interdependent States and Mercantile Guilds). Since the setting averts the All Planets Are Earthlike trope, only one extrasolar planet capable of supporting human life has been found in the explored galaxy - End. The rest of the systems are filled with artificial habitats either built in space or dug into the surface of lifeless rocks. For some reason, the Flow link to Earth has disappeared over a thousand years ago. Only the creation of the Interdependency has saved humankind from total collapse. Besides being a unifying body, the Interdependency remains true to its name by ensuring that every human settlement was in some way dependent on others, thus precluding any interstellar wars and encouraging cooperation.
The Interdependency is ruled by the emperox (the "x" is silent), who is always a member of the ruling House of Wu, whose dynasty goes back to the founding of the Interdependency over a thousand years ago. The reigning Emperox Attavio VI is on his deathbed, his heir apparent is his bastard daughter Cardenia Wu-Patrick (an Unexpected Successor, following her half-brother's tragic death while racing), who takes the name Grayland II upon ascending to the throne at her dying father's suggestion. Each emperox carries an implant that periodically uploads his or her experiences (both sensory and internal) to the Memory Room, a special room at the palace that only the ruling emperox may enter in order to converse with the holographic recreations of his or her ancestors to seek their guidance. The political and economic center of the Interdependency is located in the Hub system, named so because it serves as a literal hub of the Flow connections, leading to the majority of the inhabited systems. This allows House of Wu to charge tariffs for all transits through Hub. Other noble Houses and Guilds retain their own monopolies and control their own systems.
As preciously mentioned, End is a singular planet in the Interdependency in that it is capable of supporting life. The reason it's called "End" is that it's located in the farthest system from Hub, taking nine months to traverse the Flow connection between Hub and End. Since the vast majority of Interdependency citizens are used to living in artificial habitats, they view living on the surface of a planet as something strange and undesirable. As such, End is treated as the backwater world, where all undesirables are shunted off to. Because of that, End is also the only Interdependency world to have restrictions on leaving, reinforced by the Imperial marines in orbit. The planet has frequent uprisings that have been known to result in the reigning Duke of End being deposed and executed to be replaced by the leader of the rebels. Imperial forces are ordered not to intervene, as the Interdependency considers such occurrences an internal matter.
The Collapsing Empire focuses on three point-of-view characters: the newly-crowned Emperox Grayland II, Lord Marce Claremont (a Flow physicist and son to the Count of Claremont, a province on End), and Lady Kiva Lagos (daughter to Countess Huma Lagos of the mercantile House of Lagos, who has inherited her mother's penchant for Cluster F Bombs). The three characters get involved in the latest and, possibly, biggest crisis the Interdependency has ever faces: The upcoming collapse of the Flow network, spelling doom for the Interdependency.
The second book's preliminary title was The Last Emperox, but changed to The Consuming Fire.
The series provides examples of:
- Action Girl: Marce's sister Vrenna, former Imperial Marine, now head of her father's constabulary. She single-handedly rescues him after Ghreni has him kidnapped.
- Aerith and Bob: The author goes out of his way to make up strange-sounding names for named characters, showing that 1500 years from now people won't be using modern-day names. Then there's Hannah Patrick, a perfectly normal 20th-21st century name in the midst of names like Batrin, Cardenia, Marce, and Ghreni.
- All Planets Are Earthlike: Averted. In the 1500 years of space exploration, only one other planet capable of supporting life has been found and settled - End. Every other planet in the known universe (47 systems) is either a lifeless rock or an equally lifeless gas giant. As such, the vast majority of settlements across the Interdependency are artificial habitats either in orbit or under the rocky surface of planets. End is the only colony where people live openly (after Earth was lost to the rest of humanity). Turns out this was only true for the free systems forming the now interdependcy. The other polities of human space tend to use more planets.
- Anything That Moves: Kiva likes to have wild sex with both men and women and even has no problem interrogating someone while riding them furiously. She does have standards, although they're pretty lax and, apparently, used to be even laxer in her college days.
- Arranged Marriage: Sort-of. While an emperox may marry whomever he or she wishes, there tends to be strong political pressure to marry a member of a powerful House in order to secure a political goal. Cardenia's late brother Rennered was planning on marrying Nadashe Nohamapetan. However, Rennered's death put an end to that, although not as far as House Nohamapetan is concerned, as they claim that the arrangement was not so much between Rennered and Nadashe as between House Wu and house Nohamapetan, implying that Cardenia has to marry a member of that House, probably Amit. When Cardenia sarcastically replies that she would rather marry Nadashe than Amit, she is calmly told that this option would be acceptable as well. In fact, she later does muse on doing just that, finding Nadashe to be far more interesting than her dull brother, but Cardenia's sexual preference is firmly in the "hetero" range, so she doesn't find Nadashe to be attractive enough from that viewpoint, especially since she knows Nadashe will attempt to turn her into a puppet for her House's interests as soon as the wedding is official.
- Artificial Gravity: All starships tend to look like long needles with one or two rotating ring sections. The rings provide rotational gravity for various purposes. For the rest of the ship, push fields are employed to provide a measure of gravity. However, instead of simulating actual gravity, push fields feel like a weight is pressing down on people and objects, although the unusual feeling goes away with time. Push fields also act Inertial Dampening during maneuvers and acceleration.
- Badass Boast: Emperox Grayland II, at the climax of The Consuming Fire:You have doubted me. Doubt me no longer. You have come to destroy me. I am not destroyed. You have come to burn me. I am the consuming fire. You will feel what it is to burn.
- Be Careful What You Wish For: Ghreni maneuvers himself into the position of acting Duke of End, just in time to find out about the Flow collapse.
- Big Bad: Nadashe Nohamapetan is the smarter of the three Nohamapetan siblings, convincing her brothers Amit and Ghreni to follow her plan to take advantage of the coming Flow crisis to secure House of Nohamapetan control over the Interdependency. This includes fomenting a revolt on End in order to depose the current Duke of End and install Ghreni as the new Duke as well as setting up terrorist attacks in Hub in order to frame End rebels. Nadashe herself was supposed to marry Rennered Wu, the heir to the imperial throne. After Rennered's death, Amit tries to marry Cardenia Wu-Patrick, the Unexpected Successor. When House Lagos threatens to blackmail House of Nohamapetan, Nadashe attempts to assassinate the Emperox, resulting in Amit's death, and tries to frame House of Lagos. When she's finally cornered by the Emperox, she resolves to make sure House of Nohamapetan succeeds, even though she is going to jail.
- Brain Uploading:
- A minor example, while the memories and emotions of every emperox are stored in the Memory Room, and the reigning emperox can converse with the holographic likeness of his/her ancestors, they're not the same person, nor do they claim to be. Since they no longer have emotions, they also don't have things like egos.
- Also, Tomas Reynauld Chenevert, formerly King Tomas XII of Ponthieu, who used the same type of tech to create a much more lifelike Virtual Ghost than those of the emperoxs. In fact, as soon as Cardenia sees Tomas, she recognizes him as royalty because he could afford to use such tech.
- The Cake Is a Lie: One of the first things Cardenia learns upon ascending to the throne is that the Interdependency was built on a lie, manufactured by the Prophet-Emperox Rachela I, founder of the Interdependency and Savior of Humanity. While the official line is that the Interdependency is necessary in order to ensure cooperation and avert war, the truth is that it's there to keep the mercantile Houses in power. The second book reveals that the reason for the Interdependency was much more mundane: the Wu family simply wanted to tax the usage of the Flow Shoals.
- Cannot Spit It Out: Cardenia about her crush on Marce. She's hesitant to talk to him about it, as she doesn't want him to sleep with her just because she's the Emperox. When she talks to the Virtual Ghost of her father about it, he tells her he used to invite women into his bed all the time. That's how she was born, after all. Some did refuse, but most agreed. She eventually does tell Marce how she feels, although she has to get some liquid courage first.
- Cluster F-Bomb: The message Ghreni gets from the Red Rose, after the bomb that Chet supposed to plant on the Yes, Sir goes off: "fucking hell those assholes took your fucking bomb and got it on our fucking ship what the actual fuck"
- Coitus Uninterruptus:
- Kiva is introduced by having a crewmember walk in on her riding a subordinate. She doesn't even pause, having just found her "groove". Only when the unfazed crewmember explains that it concerned House business is she forced to get off the subordinate and get dressed.
- In the second book, she gets a call from her assistant while receiving a "perfectly serviceable oral". She indicates to her partner she should keep at it, while accepting the call and holding a conversation. It's noted that, had the oral been more than "perfectly serviceable", she wouldn't have even bothered to answer the call.
- Cut Himself Shaving: After Kiva pays Louentintu a visit and breaks her nose, the former claims that she broke her hand "against something stupid", while the latter claims her broken nose was the result of a fall.
- Deadpan Snarker: All over the place.Grayland: I have some people here who would very much like to do that to me. Overthrow me, I mean.
Chenevert: I would recommend against it.
Grayland: Not a great career move?
Chenevert: It frees up your schedule, which is honestly fantastic. But the people who removed you then usually want to kill you too. And that's inconvenient.
- Didn't Think This Through: The extremists, who cut the Independent Systems off from the Earth Empire and the Assembly. Within a few short years, the Systems nearly collapsed from a lack of food and other supplies, as they were economically dependent on the other systems.
- Dropped a Bridge on Him: Naffa Dolg, Cardenia's best friend since college and her new chief of staff. Naffa is killed during a bombing at Cardenia's coronation.
- Earth That Was: Earth has been cut off from the rest of humanity for over a 1000 years, so no one knows what happened to the people there. However, there's no particular indication it was anything bad; in fact, it seems somewhat assumed that Earth is just going on its merry way.
- Except it turns there was an intentional effort to bury the truth after the Free Systems which formed the Interdependency engineered the Rupture after The War of Earthly Aggression ended and extremist wanted isolation from the rest of human space.
- The Emperor: The ruler of the Interdependency is called "Emperox", a gender-neutral title that is, apparently, pronounced "empero" (according to the audiobook and the Word of God). The Emperox's word is law, although the Interdependency government has other branches, such as the Parliament (composed of representatives of the noble Houses; the Emperox is also the representative of House of Wu, although he/she typically abstains from voting). Any Parliament bill can be vetoed by the Emperox, although there may be political repercussions for doing that.
- Enhanced Interrogation Techniques: In a way. After Kiva and Marce sleep together, Kiva gets back on top of him and starts riding him... while questioning him about the reason he's going to Hub. Later on, when her mother asks how she got Marce to tell her everything, Kiva's response is that she "fucked it out of him."
- More conventionally, Kiva has one of Ghreni's agents who snuck aboard her ship spaced. Briefly. When they reel him back in, he promptly spills his guts (figuratively speaking).
- Evil Cannot Comprehend Good/Good Cannot Comprehend Evil: Pops up in The Consuming Fire, damaging relations between the throne and the Countess Nohamapetan - Cardenia offers to commute Nadashe's sentence to a Luxury Prison Suite, intending this as an olive branch (and this is how Kiva sees it), but the Countess can only parse this as an attempt to keep Nadashe hostage; Cardenia knows she messed up somewhere in the interaction, but has no idea where. Also, the Countess's hunger for power means that in the middle of a Villainous Breakdown, she blurts out her assassination of Rennered Wu as though Cardenia should view this as a favour, unable to comprehend that Cardenia didn't want the throne in the first place and views it as an inconvenient responsibility that nevertheless she has to execute as best she can.
- Everyone Calls Him "Barkeep": The Duke of End is never given a name, and always referred to by his title.
- Faking the Dead: Nadashe, though it only lasts until the end of Consuming Fire.
- False Flag Operation: The bombings in the Hub system are attributed to End's rebels, and all evidence points to them. In fact, the people behind them are the rulers of House Nohamapetan, trying to provoke a military intervention. Later on, a shuttle slams into a ship, where Cardenia and Amit are touring, and evidence implicates House Lagos. Except, once again, it's the Nohamapetans.
- Feudal Future:
- Foreshadowing: When the narration talks about Rennered Wu's death, it mentions that while the report made it clear it was an accident, it also said that such an accident should have been unlikely, and that Rennered was supposed to announce his engagement to Nadashe after the race was over, something that had stuck with Cardenia/Grayland. The Consuming Fire reveals that while Nadashe wasn't behind it, her mother was, because Rennered was about to back out of their engagement.
- Gone Horribly Wrong: Marce concludes that the collapse of the Flow shoals is partly the result of the Rupture, engineered by the Independent Systems extremists prior to the formation of the Interdependency, which cut the Systems off from the other human polities.
- Horrible Judge of Character: Senia Fundapellon, who serves as lawyer for the Nohamapetans. This changes pretty quickly after she gets shot in an attempt on Kiva's life.
- Hyperspace Is a Scary Place: There is no space/time inside the Flow. This is why all ships must generate their own bubble of space/time before entering a Flow Shoal lest they cease to exist. Anything that leaves the bubble in the Flow ceases to exist instantly. In addition, ships are designed exclusively for in-system travel, so any ship that ends up somehow leaving the Flow in interstellar space is doomed. The fate of one such ship is described in gruesome detail in the second book, and even the recordings of the final surviving crewmember are stated to be lost forever, since no living being would ever lay eyes on the ship again.
- Hyperspace Lanes: The Flow connects only some of the known stars, making it impossible for humans to go anywhere else within a reasonable time frame. As a rule, each Flow connection is a bidirectional, although that's only the public's perception, as, technically, they are completely separate streams that aren't connected to one another (e.g. the Hub->End stream is not the same as the End->Hub stream). Hub is uniquely situated on a focal point of dozens of Flow links, making it the most important system in the Interdependency.
- Interfaith Smoothie: The Church of the Interdependency is the official religion of all of humanity. It was deliberately designed to focus less on the nature of the supreme force/being/deity and more on how people ought to behave. This appears to result in less faith-based conflict. It's implied that other religions still exist, such as Christianity, but they're marginalized. The Emperox is the official head of the Church. In fact, the true purpose of the Church was to sell the idea of an Interdependency to the public, with Rachela Wu claiming to have seen visions to that effect.
- It's Personal: Kiva's efforts to bring down House Nohamapetan become this after Senia, now Kiva's lover, gets hurt in an attempt on her life by the Countess.
- Lady Killer In Love: Kiva is surprised to find herself developing a thing for Senia.
- Locked Away in a Monastery: Emperox Attavio VI gave the Count of Claremont his position as tax auditor on End on the condition of silence. This is because the Count's real purpose on End was to study the potential collapse of the Flow streams, a delicate subject that could easily cause alarm.
- Morality Kitchen Sink: Some characters, such as Cardenia Wu-Patrick and Marce Claremont, are good. Some, like Lady Kiva Lagos, are amoral but not evil, and sometimes on the side of good. And some, like Nadashe Nohamapetan—who kills her own brother, among others—and like her mother are evil, ruthless, power-hungry sociopaths.
- Musical Theme Naming: The House of Lagos tends to name its ships based on song lyrics, specifically the song "Yes, Sir, That's My Baby". The ship Kiva is on is actually called Yes, Sir, Thats My Baby (Yes, Sir for short), while her sister ship is called No, Sir, I Don't Mean Maybe (No, Sir for short).
- The Mutiny: The prologue of The Collapsing Empire starts with a mutiny aboard the Tell Me Another One, a starship owned by the House of Tois. The mutineers are led by the ship's executive officer, who plans to sell their cargo (weapons for the Duke of End to crush the rebellion there) to the End rebels via Space Pirates. They almost succeed, but then the Tell Me drops of the Flow early, something that never ever happens. Both sides forget their differences and work together to get back in the Flow, lest they be stuck forever in interstellar space. As soon as they succeed, The Captain kills her XO and crushes the mutiny. Later, it's revealed that she decided to follow-up on her XO's plan anyway and sold the weapons to the pirates but was caught and detained by the Imperial authorities on End.
- No Periods, Period: Averted. Cardenia is unlucky enough to have her period during her coronation, making the uncomfortable situation even worse.
- No Pronunciation Guide: Some of the names are a bit difficult to figure out without one, given that the author deliberately went out of his way to make them up. It's a bit easier with the audiobook version, as, one assumes, Wil Wheaton was told by Scalzi how to say certain words/names. For example, Ghreni actually sounds almost exactly like "granny". The biggest offender is the word "emperox", which is, apparently, supposed to be pronounced as "EM-per-oh" (i.e. the "x" is silent).
- Reality Ensues:
- Any scientist, no matter how brilliant, needs peers to check their work. This is why Marce and his father, who could find each others' mistakes, got more accurate results than an equally brilliant scientist in the pay of the Nohamapetans. And why in the sequel Marce and his father missed the evanescence.
- Hatide Roynold ends up being blacklisted as a scientist, since her research was what caused the Nohamapetans to start their coup.
- Really Gets Around: Lady Kiva. Not only was she introduced mid-coitus, but all of her appearances in the series involve her thinking about, mentioning, or having sex with someone.
- Right for the Wrong Reasons: The Nohamapetans are completely correct that End is about to become the most important system in the Interdependency. They just think that it's because the Flow streams are about to shift, making End the new Hub, rather than collapse completely.
- Royals Who Actually Do Something: Generally played straight, as leaders of the Houses tend to also run their financial empires. Their scions either work in the family business or have regular jobs. As for minor nobles, such as the Count of Claremont, his official job is to assess Imperial taxes on End (it's just a cover for his real job - figuring out what's going on with the Flow). The Count's children are a physicist and a former Imperial marine.
- Seers: The first emperox claimed to have seen visions of a unified humanity, which is why she is always referred to as Prophet-Emperox Rachela I. The Church tends to downplay the actual visions and focuses on the day-to-day of taking care of the spiritual needs of the public. In the second book, Emperox Grayland II claims to be seeing visions of the Flow collapsing, bringing an end to the Interdependency. This creates a crisis, since the Church doctrine technically allows for any of Rachela's descendants to be a prophet too, but no emperox since Rachela has actually claimed to see genuine religious visions (as opposed to hallucinations) in nearly a thousand years.
- Sir Swears-a-Lot: Kiva has to make a conscious effort to make a sentence without at least one swear word in it. She appears to have picked that up from her mother, Countess Huma Lagos. According to the family legend, Kiva's first word was "fuck", something she believes to be true.
- Shout-Out: The mercenary ship in the second book is named The Princess Is in Another Castle.
- Shut Up, Hannibal!: After Countess Nohamapetan blurts out that she had Cardenia's half-brother killed and acts like she owes her everything because of it, Cardenia replies "Lady, I don't owe you shit."
- Spaceship Girl: A male version with Tomas Reynauld Chenevert, the Virtual Ghost who also runs the ship Auvergne.
- Tempting Fate: As Ghrenni reflects on how badly his efforts at getting back Marce have gone, he thinks to himself that at least he doesn't have the Duke of End screaming at him, too. Naturally, who should call him but a very unhappy Duke of End.
- Title Drop: Done twice so far:
- In the first book, Count Clairemont refers to 'The collapsing empire' at the end of chapter four.
- In the second book, Cardenia refers to herself as 'the consuming fire' in her Badass Boast to Countess Nohamapetan and her co-conspirators.
- Thrown Out the Airlock: Kiva interrogates Chat Ubdal by briefly doing this, and then dragging him back in. After the crew of the Red Rose's attempts to kidnap Marce go royally south (partly because Kiva's crew passed off a disguised Chat as Marce), he gets spaced permanently.
- Try to Fit THAT on a Business Card!: The official title of the Emperox is "Emperox of the Holy Empire of the Interdependent States and Mercantile Guilds, King/Queen of Hub and Associated Nations, Head of the Interdependent Church, Successor to Earth and Father/Mother of All, <ordinal number> Emperox of the House of Wu, which claimed its lineage to the Prophet-Emperox Rachela I, founder of the Interdependency and Savior of Humanity." Even the full name of the Interdependency is never used outside a ceremonial setting.
- Unexpected Successor: Cardenia Wu-Patrick is the bastard daughter of Emperox Attavio VI. She was never raised as a princess and did not expect (or want) to inherit the throne, leaving it to her half-brother Rennered, who was actually groomed for the role. After Rennered's tragic death during a race, the dying Emperox makes Cardenia his chosen heir instead of any number of cousins and nephews/nieces. Cardenia only has a few months to process the shock before she has to formally step up to her new office.
- Unproblematic Prostitution: There's an offhand mention that makes it clear sex work is just like any other industry in the Interdependency—which is to say, totally monopolized by a single mercantile House.
- Villainous Breakdown: The Countess loses control in The Consuming Fire as Cardenia disassembles her coup in about five minutes, blurting out that she assassinated Rennered and essentially gave Cardenia the throne, seemingly expecting Cardenia to view this as a favour to be repaid. Cardenia, unsurprisingly, tells her where to stick it.
- Virtual Ghost: See Brain Uploading above.
- Xtreme Kool Letterz: The reason the Wu family chose the title "emperox" over "emperor/empress". You can thank their marketing people for that.
- You Have Outlived Your Usefulness: After Teran Assan successfully breaks Nadashe out of captivity, Countess Nohamapetan calls him up and tells him this in so many words, just before his own mercenaries leave him to die with the fake dead Nadashe.