Tessa Gray is settling into her new life with the Shadowhunters. However, the disaster that led to Mortmain escaping, as put Charlotte under pressure. Some Shadowhunters do not believe she is capable of running the London Unit and she now has to prove she can find Mortmain.
Will, Jem and Tessa are determined to help Charlotte keep her position and fight against a takeover by the Lightwood family. Will also asks Magnus to help him track down a demon that cursed him as a child and is the reason why he won't let anyone close.
There seems to be be two main storylines in this instalment. Will is hunting the demon that cursed him as a child, so that he can lift it, and hopefully win Tessa's affections. However, Tessa and Jem grow close and start a secret relationship. All this while the group are trying to track down Mortmain , his clockwork creations and also protect Will's family. They learn that some Shadowhunter familes are in colusion with Mortmain for their own reasons. The love storylines are a little bit distracting, as Tessa is constantly pulled between Jem and Will. The hunt for Mortmain is the more interesting storyline, especially when it unearths the secrets behind the Lightwood family. I was frustrated that there was no questions answered about Tessa's origins. However, the characters are better established in this instalment and there are some betrayals that comes to the fore. Interesting twist at the end for Will too.