Clockwork Princess

Clockwork Princess is a 2013 fantasy novel written by young adult author Cassandra Clare. It is the third and final installment of The Infernal Devices trilogy, following the first book, Clockwork Angel, and the second book, Clockwork Prince. It is written in the third person through the perspective of the main protagonist, Tessa Gray, who resides in the Shadowhunter's London Institute. 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.