Sebastian is targeting institutes all over the world and is turning the Shadowhunters there into darker versions called the Endarkened. With Emma, Julian and the rest of the children, the only ones to survive the attack on the Los Angles institute, every Shadowhunter withdraws to Idris to develop a plan of action to stop Sebastian. There is only one weapon that can defeat Sebastian, Heaven Fire, but it is in Jace and he has no control over it. When the Nephilium are betrayed by an ally, Clary and Jace along with Isabelle, Simon and Alec must travel to the demon realms. With Sebastian wanting to get his hands on Clary and Jace, will the young Shadowhunters and vampire be able to survive the battle that is coming which decides the fate of the world?
City of Heavenly Fire is the brilliant final book of the Mortal Instruments, it is a big book but is never dull as it has action, politics and romance. This book is better than the last two books in this series and is up to the standard of the first 3 books.
Clary is stronger and has grown over the last 6 books as she knows who she is and what she wants. Jace is more open and we get to see the real Jace behind the mask and, even with the Heavenly Fire in him, his and Clary’s relationship is the most stable and happiest it has been in this series. As well as familiar characters there are some new characters, Emma and Julian, which gives us a nice glimpse into the next series
While I have really enjoyed this series, I am glad it is over as I feel that these characters stories have finished. I am looking forward to the next series The Dark Artifices and seeing how Emma and Julian have grown up. I would recommend City of Heavenly Fire to everyone who enjoyed the rest of the Mortal Instruments and this series to fans of paranormal books.