The Disciples are being manipulated by beings older than time, and only Kernel Fleck knows that something is wrong.

Trust is dangerous, and to love is to destroy. Plunge into the fourth installment in the internationally bestselling Mortal Instruments series and "prepare to be hooked" (Entertainment Weekly).
The Mortal War is over, and sixteen-year-old Clary Fray is back home in New York, excited about all the possibilities before her. She's training to become a Shadowhunter and to use her unique power. Her mother is getting married to the love...

Ashley and Billy, aided by the dragons, their friends, and a powerful, ancient book, each take courageous steps to rescue loved ones from Morgan Le Faye and her demonic Watchers.

Still pursuing a cure for her mother's enchantment, Clary uses all her powers and ingenuity to get into Idris, the forbidden country of the secretive Shadowhunters, and to its capital, the City of Glass, where with the help of a newfound friend, Sebastian, she uncovers important truths about her family's past that will not only help save her mother but all those that she holds most dear.