Cassandra Clare 
Clockwork Princess 

Danger and betrayal, love and loss, secrets and enchantment are woven together in the breathtaking finale to the #1 New York Times bestselling Infernal Devices Trilogy, prequel to the internationally bestselling Mortal Instruments series.Danger intensifies for the Shadowhunters as the New York Times bestselling Infernal Devices trilogy comes to a close. If the only way to save the world was to destroy what you loved most, would you do it? The clock is ticking. Everyone must choose. Passion. Power. Secrets. Enchantment. Danger closes in around the Shadowhunters in the final installment of the bestselling Infernal Devices trilogy.