City of Heavenly Fire by Cassandra Clare
This big book wraps up The Mortal Instruments series. It provides a strong, satisfying conclusion to the novels, full of the action and relationship angst that characterized the other books. The violence gets taken up a notch as the villain Sebastian/Jonathan makes an evil army by turning Shadowhunters into Endarkened by forcing them to drink from the Infernal Cup. The main characters spend much of the second half of the book pursuing him into a nightmarish demon realm. Clare shows she’s got the guts to kill off some second-tier characters. The ending also brings together contemporary characters from this series with the surviving characters from the prequel series The Infernal Devices, creating a sense of far-reaching history and genealogy. (I read that series before I picked up any of The Mortal Instruments books, but now I think that reading them in the order they were written would be best, because then the reader wouldn’t experience a dip in quality between Clare’s later books and her first novel.) Again, the love story plotline is the stuff of a teen girl’s daydreams, as Jace spouts lines about how Clary has changed him for the better as they bask in their happy ending.
The ending is mostly closed for the main characters, but open enough to allow a spin-off series with new characters introduced in this book. The Mortal War ended with some discontentment–the vanquished fairies stripped of power and Shadowhunters displaying some racist attitudes. There are just enough loose ends to begin a new series and tantalize readers between books, while our heroes get to have their happily ever after.