Jem collapses from his illness and learns about Will's unrequited love for Tessa, before urging him to save her in his stead. Before she dies, she leaves clues for Will and Cecily about where Mortmain is taking Tessa to: Cadair Idris. Black attack the Institute and mortally wounds Jessie before taking Tessa away. On the day of her arrival, automatons and Mrs. Gideon steadfastly refuses, but Gabriel has to go through some time before he finally chooses to side with Charlotte.Īfter undergoing trials at Silent City, Jessamine Lovelace is sent back to the London Institute. Meanwhile, Consul Josiah Wayland, now increasingly frustrated by Charlotte Branwell's refusal to be his lapdog, attempts to convince Gideon and Gabriel to betray her in exchange for the Lightwood's honor to be restored.

Jem refuses to even consider the offer and convinces Tessa to do the same, so they decide to move the date of their wedding earlier.

However, Axel Mortmain has bought all of London's stock of yin fen, wanting to blackmail the Institute into handing over Tessa in exchange for the drug. Jem gets sick faster and Will realizes that he has taken an unusually higher dosage of yin fen so he can stay stronger for the wedding. Gabriel moves to the London Institute and develops a relationship with Will Herondale's sister, Cecily, who has also taken residence in the Institute after failing to convince Will to return home, much to Will's annoyance. At the end, Gabriel and his brother, Gideon, have no choice but to kill their father, creating a rift between the brothers and Tatiana. Gabriel Lightwood arrives at the Institute and requests help in taking care of his father, Benedict, whose demon pox has turned him into a worm, killing the Lightwood's servants and Rupert Blackthorn, the husband of his daughter, Tatiana. Two months after the events of the previous book, Tessa Gray is in the midst of preparing for her wedding to Jem Carstairs. This final installment follows Tessa and her friends as they face off against the series main antagonist, The Magister (also known as Axel Mortmain), who plans to completely obliterate the Shadowhunter race. It is written in the third person through the perspective of the main protagonist, Tessa Gray, who resides in the Shadowhunter's London Institute. It is the third and final installment of The Infernal Devices trilogy, following the first book, Clockwork Angel, and the second book, Clockwork Prince. Clockwork Princess is a 2013 fantasy novel written by young adult author, Cassandra Clare.

Infernal devices series