This third book in the series brings together a few storylines and sets up the final showdown with Valentine. Jace and Clary are still fighting against their feeling for each other, and this instalment we learn the truth about Jace and what Valentine did to him as a child.
Also a new character comes into Clary life, Sebastion, who is curiously intense about her.
Most of the book is based in the world of the Shadowhunter. Simon is caught up with the politics and bad feeling against Downworlders. But when Valentine's Demon army attack the Shadowhunter's in their own city, there only hope is trying to work with Downworlders to survive.
There is a lot of filling in storylines throughout the plot, which did slow things down for me. Took a while to learn about the source of Jace and Clary's powers and the final confrontation with Valentine didn't appear until near the end of the book. Not enough action for me in this book, but still reasonably enjoyable read.