Clockwork Prince is a 2011 novel by Cassandra Clare. It is the second book in The Infernal Devices trilogy and a prequel to The Mortal Instruments series. The book is about Tessa Gray, who has found safety with the Shadowhunters in Victorian London. However, the Magister wants to use Tessa's powers for his own dark ends. With the help of Will and Jem, Tessa discovers that the Magister's war on the Shadowhunters is fueled by revenge. Loved this trilogy - highly recommend if you love the shadowhunter world that Cassie Clare has created. Excellent condition - smoke free, pet free home. :)