Editors Reads
City of Lost Souls by Cassandra Clare — book cover

City of Lost Souls — The Mortal Instruments, Book 5

by Cassandra Clare · Margaret K. McElderry Books · 534 pages ·

4.1
Reviewed by James Hartley

Jace has disappeared — taken and bound to Sebastian Morgenstern — and Clary must go undercover to find him, pretending to join Sebastian while searching for a way to free Jace from the demonic tie that controls him. The stakes are higher than ever as Sebastian prepares to raise an army.

Check Price on Amazon (paid link) Opens Amazon · Prices subject to change

Editors Reads Verdict

The fifth book raises the stakes on the second arc considerably. Clary embedded with the enemy and Jace compromised by dark magic create genuine tension, and Sebastian emerges as a villain with real menace. The best entry in the second trilogy.

4.1
Check Price on Amazon (paid link)

What We Loved

  • Clary undercover inside Sebastian's inner circle is the most psychologically tense setup the series has staged before this point
  • Sebastian is a more effective villain than Valentine at this stage — intimate and present, his monstrousness visible in small moments not grand speeches
  • The Jace-is-compromised premise sustains genuine tension across the full book rather than just a climactic act
  • Isabelle and Alec's relationship continues to develop with real complexity that rewards series investment

Minor Drawbacks

  • The demonic binding mechanics, while coherent, require explanation that occasionally slows the novel's pacing
  • The global stakes, while proportionate, can make the intimate Clary/Sebastian dynamic feel incongruously small by comparison
  • Readers who found the second trilogy's opening slow may not persist far enough to reach this stronger entry

Key Takeaways

  • Infiltrating an enemy requires performing loyalty so convincingly that the line between performance and reality begins to blur
  • Evil that is intimate — living alongside it, pretending to accept it — is more corrosive than evil that is distant
  • A magical bond that compromises someone you love forces a choice between the person and the fight against the force controlling them
  • The most effective villain creates situations where defeating them requires becoming something you would not otherwise be
Book details for City of Lost Souls
Author Cassandra Clare
Publisher Margaret K. McElderry Books
Pages 534
Published May 8, 2012
Language English
Genre Fantasy, Young Adult, Paranormal Romance

City of Lost Souls Review

City of Lost Souls is the best book of the Mortal Instruments’ second trilogy and, arguably, the strongest in the series since City of Glass. Clare places Clary in the uncomfortable position of infiltrating Sebastian’s inner circle, pretending to be won over to his cause while searching for a way to free Jace from the magical binding that has made him complicit in Sebastian’s plans. It is a more psychologically tense setup than the series has staged before.

Sebastian Morgenstern is a more effective villain than Valentine was at this point in his arc — Valentine’s ideology was coherent but distanced; Sebastian is intimate and present, his monstrousness visible in small moments rather than grand speeches. The dynamic between Sebastian and Clary, as she navigates her undercover role, is the book’s most compelling thread.

What works: The Jace-is-compromised premise generates sustained tension across the full book rather than just a climactic act. Isabelle and Alec’s relationship continues to develop with real complexity. The stakes are global in a way that feels proportionate to where the series has come.

The magic mechanics: Clare’s demonic-binding system is well-explained and used coherently throughout the plot.

Verdict: Essential reading for series completists, and the entry most likely to win over readers who found the second trilogy slower to engage.


Reading Guides

Frequently Asked Questions

What is "City of Lost Souls" about?

Jace has disappeared — taken and bound to Sebastian Morgenstern — and Clary must go undercover to find him, pretending to join Sebastian while searching for a way to free Jace from the demonic tie that controls him. The stakes are higher than ever as Sebastian prepares to raise an army.

What are the key takeaways from "City of Lost Souls"?

Infiltrating an enemy requires performing loyalty so convincingly that the line between performance and reality begins to blur Evil that is intimate — living alongside it, pretending to accept it — is more corrosive than evil that is distant A magical bond that compromises someone you love forces a choice between the person and the fight against the force controlling them The most effective villain creates situations where defeating them requires becoming something you would not otherwise be

Is "City of Lost Souls" worth reading?

The fifth book raises the stakes on the second arc considerably. Clary embedded with the enemy and Jace compromised by dark magic create genuine tension, and Sebastian emerges as a villain with real menace. The best entry in the second trilogy.

Ready to Read City of Lost Souls?

Check the current price on Amazon.

Check Price on Amazon (paid link)

Prices and availability are subject to change. See Amazon for current price.

Affiliate Disclosure: As an Amazon Associate I earn from qualifying purchases. Clicking Amazon links and purchasing may earn us a small commission at no cost to you. Our reviews are editorially independent — affiliate relationships do not influence our ratings or recommendations. Product prices and availability are subject to change; see Amazon for current pricing.
#cassandra-clare#shadowhunters#mortal-instruments#ya-fantasy#urban-fantasy#paranormal

Review last updated:

Skip to main content