Cassandra Clare 
Infernal Devices 3: Clockwork Princess 

Danger and betrayal, secrets and enchantment in the breathtaking conclusion to the #1 New York Times bestselling Infernal Devices trilogy, a prequel series to The Mortal Instruments. The Mortal Instruments: City of Bones is in cinemas August 2013.Danger and betrayal… Secrets and enchantment… Third and final book in the bestselling prequel series to The Mortal Instruments, set in Victorian London. A net of shadows begins to tighten around the Shadowhunters of the London Institute. Mortmain needs one last item to complete his plan. He needs Tessa. But Jem and Will, the boys who lay equal claim to Tessa’s heart, will do anything to save her. Read all the sensational books in The Shadowhunter Chronicles: The Mortal Instruments, The Infernal Devices, Tales from the Shadowhunter Academy, The Bane Chronicles, The Dark Artifices, The Last Hours and The Shadowhunter’s Codex.