Clockwork Princess is the last volume of the Infernal Devices series by Cassandra Clare. If you haven't read Clockwork Angel and Clockwork Prince you might not want to read my review as it contains spoilers.
The book opens a few months after the last events of Clockwork Prince. We find Tessa and Jem engaged, Will, his curse lifted, madly in love with Tessa and Gideon Lightwood living at the Institute. The peace is immediately disturbed by Gabriel Lightwood's call for help; Benedict Lightwood, now a gigantic demonic worm, is terrorizing Lightwood manor. The Shadowhunters fly to the rescue.This first battle start the chain of event that will eventually lead them to Mortmain and his evil plans.
Despite the combat at Lighwood mansion at the begining of the book, the first half of it is very much about the love triangle and Jem's slow death. Suddenly, the novel fully becomes a teen love story with much ansgt, sacrifice and pain. It drags on for a few hundred pages and robs the the novel of its usual fast pace. Finally, when the main action begins, Clare goes back to her usual rythm but even after what should be the end of the story, she goes back to describing Will's courtship of Tessa. This does not take into account the two other love stories that add their weight to the narrative.
At this point in the series, the readers are well aware that Jem is half-Chinese and that Will is Welsh. Yet, with Tessa now able to understand a little Chinese and Cecily (Will's sister) living at the institute, the reader is constantly overwhelmed by an unnecessary number of Chinese and Welsh dialogue lines, most of which are not translated. It feels like the author is trying to show off her language skills and it hinders the reading.
Despite all this, Clare does tie the whole story together and there are no loose ends. There are surprises and unexpected turns that delight the reader. The author also manages to create interest for the following series, The Mortal Instruments, with an open ending.
As a whole, I feel The Infernal Devices series has a promising start but loses its strenght and momentum as the love story develops to become the central element of plot. I still recommend it; Clare's prose is, in general, a delight to read and improves with each volume. However, the reader should be aware that the series is mainly an angsty love story and that the world Shadowhunter comes second.