The first forty percent of the book are spent developing the main characters. The characters are mostly leftish artists and scientists. Except Yag, an avian humanoid who came to town to find someone who could provide him with the means to fly after his wings were removed as a punishment. Derkhan is a leftwing journalist who writes for an illegal working class paper and is does a bit of art as cover. Isaac is a crackpot scientist who would rather work in obscurity than play department politics at the University. Lin is a humanoid insect creature, a sculptress of some minor renown, and Isaac's lover. Interspecies love is frowned upon and the tension between their desire for each other and their fear of retribution drives their internal life for the first part of the book. Lin and Isaac travel in a circle of progressive political activists, artists, criminals and intelligentsia and while we learn about most of these characters early on, they sadly don't have very much to do with the rest of the story.
Several disparate plot elements are introduced in the first section, though it quickly becomes apparent that this is to explain an unlikely set of coincidences later rather than develop a particularly intricate story. By the time the 'Introduction' section is finished, all of the plot pieces are on the board and it's clear to the reader how the pieces will ultimately fit together.
The city becomes infested with soul-eating moths that have the ability to prey on sentient beings with the ease that cats prey on mice. They are bigger, stronger, faster and can mesmerize hominids with their polychromatic wings, paralyzing them in a stupor while the moths eat their souls and leave a personality-less husk behind. During the course of this infestation, Isaac and his merry bend of misfits fall under the scrutiny of the authorities, and find themselves surrounded. Enter The Weaver, an eightlegged, 10 feet tall spider with Mary Sue written all over it. I was disappointed in this character, as The Weaver is used over and over to get the characters out of trouble. I feel like the story should have been about the Weaver and how she/it helped some humans take care of a moth problem.
During this section, character development basically comes to a standstill. Lin and Isaac get separated, and Isaac has reason to believe Lin is dead. We read about this, but we don't see any real change in Isaac or his behavior. It's like a footnote - and the gang keeps working on their Big Technological Revolution that will take care of the moths and also change the nature of scientific inquiry and industry for generations.
I don't feel like I'm giving away a spoiler when I say they are able to eradicate the moth infestation. Our heroes are on the lam from the authorities, the mechanized underworld and the criminal boss. Holed up in a shack, they make no effort to spread the technology they developed; no effort to help the oppressed throw off their chains and overthrow their hypercapitalist overlords. We learn more about why Yag's community cut his wings off - in a way that does not seem plausible, and this drives the final piece of action. Isaac and Derkhan take the injured Lin and abandon Yag to his fate. I wanted to see Isaac have a conflict about putting Lin out of her misery, but this was neatly avoided. Yag does have a bit of an existential moment when he realizes that Isaac has abandoned him and will not develop a way for him to fly again, but ultimately it's not satisfactorily resolved, IMHO.
This is a lavish book, full of metaphors and similes and words like "bituminous" and "obstreperous". It's a vivid, well thought out world that is self consistent and makes sense. There are millions of stories to be told in the metropolis of New Crubuzon. I felt it unfortunate that this story did not get the attention that the setting did. The pacing was a bit jarring, the characterization lurched from one choice to another, and the plot was simple.
But the setting. Wow. I would happily play an RPG set in this world, just because of the richness and intricate interplay of all the different species, factions and socioeconomic strata. I would eagerly buy an anthology of shorts written by different authors in this setting, but I don't feel excited about reading anything this long from China again.