This is the second book in the Mortal Instruments series by Cassandra Clare.
The book follows on from where we left Clary and Jace in City of Bones, they are both a little lost and confused and trying to fight the feelings they have for each other.
In this book we are introduced to some new members of the clave, such as the high inquisitor as well as some new Downworlders in the Steelie Court.
The main story in this book is that someone is killing Downworlder children, Clary and Jace try to discover who is behind these murders without acting on their romantic feelings towards each other.
This book was a bit more fast paced than City of Bones, which I preferred. Especially for a sequel, we already know about the main characters and now we want to see some action! Trust me this book does not disappoint in that department!