The novel “Chasm City” by Alastair Reynolds was published for the first time in 2001. It’s part of the Revelation Space universe. It won the British Science Fiction Association award.

Tanner Mirabel is a security expert who for years oversaw the protection of a powerful man on the planet Sky’s Edge and of his wife. When the two of them are killed, Tanner is taken by the lust for revenge and chases Argent Reivich, the instigator of the double murder, to the planet Yellowstone. That’s an inhospitable planet where, however, they built Chasm City, a habitat composed of huge shape-shifting skyscrapers. When he arrives, however, he discover that the city was devastated by an alien plague.

The interstellar voyage lasted years, spent by Tanner in cryogenic suspension. When awakened he suffers from amnesia and before starting his manhunt he must try to recover his memories. As if the situation weren’t complicated enough, he discovers he’s been infected with an indoctrination virus that causes flashbacks where he relives the memories of Sky Haussman, an important figure of the past of his home planet by someone considered a religious figure and bye others a criminal.

“Chasm City” is set in the same fictional universe of “Revelation Space” but can be read independently. It mentions the Sylveste family, the protagonist of the first novel, and the plague that devastated Chasm City is the same that in the first novel struck the captain of the starship “Nostalgia for Infinity”. For the rest, however, the story told in “Chasm City” is completely separate and concerns other characters.

The protagonist of “Chasm City” is Tanner Mirabel, who makes a journey from the planet Sky’s Edge to Yellowstone to avenge the murder of the people he was supposed to keep safe. When he arrives in Chasm City, instead of finding the most advanced technology ever created by humans, he discovers that an alien plague has struck all kinds of nanomachines, both the ones in the inhabitants’ bodies and the ones used for other tasks.

Most of the survivors were forced to recreate primitive equipment while some aristocrats were able to insulate their nanomachines and can continue to live not only in luxury in their part of Chasm City but also being potentially immortal.

Like “Revelation Space”, “Chasm City” is also split in various subplots, in this case set in different periods. One problem of the first novel was that often there were characters telling other ones stories of their past and this way to provide information made the story heavier. Instead, in the second novel the past is shown in the form of memories of the protagonist Tanner Mirabel and that helps to have a pace generally fast with a lot of action.

Memory is a fundamental theme of “Chasm City” and it’s closely related to that of identity. When Tanner Mirabel wakes up at the end of his journey to Yellowstone he makes two discoveries related to his memories. The cryogenic suspension caused him amnesia and he’s been infected with an indoctrination virus that makes him remember scenes from the life of Sky Haussman which mostly involve his journey with the flotilla of generational starships towards the system of the star 61 Cygni.

The subplots of “Chasm City” tell the story of Tanner Mirabel in Chasm City, his memories of what happened to him on Sky’s Edge and those of Sky Haussman. The recovery of his memories and flashbacks induced by the indoctrination virus have various cumulative effects on Tanner and inevitably influence him. Tanner’s memories are narrated in the first person from his point of view while the Sky’s ones are narrated almost entirely in the third person.

This narrative allows the readers to gradually discover the Tanner and Sky’s past in the end allowing them to understand the situation of the planet Sky’s Edge. From the beginning of “Chasm City” we know that it’s a planet where there are almost constantly warring factions and the flashbacks shed light on its history.

The various subplots include the presence of people who are potentially immortal, who typically don’t seem very mentally stable. Overall, considering the events of Yellowstone, what comes out is a really cynical portrait of humanity because if humans who enjoy longevity treatments tend to be bad the others are not necessarily good. It’s as if “Chasm City” Alastair Reynolds concentrated all the worst of humanity.

The overall plot that results from all the subplots is complex and rich in elements, maybe not original but combined mostly in a intelligent way. I think the main problem with “Chasm City” is that the plot relies a bit too heavily on coincidences. It’s a plot device commonly used but in this novel it seems that the main character always manages to be in the right place at the right time to meet the right people who allow him to have access to various secrets, even those who are supposed to be kept with great care.

The many twists and turns that eventually lead to uncover the truth about Tanner Mirabel and his motives, about what happens in Chasm City and on Sky’s Edge aren’t always convincing. Actually, in some cases the plot developments make more sense after a while, when some secrets are revealed. Similarly, the novel initially appears to make use of some clichés, starting with Tanner’s perrsonality, but going forward we understand that everything is more complex than it seems and the protagonist ends up being well developed.

“Chasm City” is in some ways better and in some others worse than “Revelation Space”. Overall, I found it really good for the mixture of themes and elements that make it impossible to include it in a single sub-genre, a science fiction one or something else. If you’re not scared by its 500+ pages, I recommend reading it.