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 of her life. Downworlders and Shadowhunters are at peace at last. And--most importantly of all--she can finally call Jace her boyfriend.

But nothing comes without a price.

Someone is murdering Shadowhunters, provoking tensions between Downworlders and Shadowhunters that could lead to a second, bloody war. Clary's best friend, Simon, can't help her--his mother just found out that he's a vampire, and now he's homeless. When Jace begins to pull away from her without explaining why, Clary is forced to delve into the heart of a mystery whose solution reveals her worst nightmare: she herself has set in motion a terrible chain of events that could lead to her losing everything she loves. Even Jace.

The stakes are higher than ever in the #1 New York Times bestselling fourth installment of the Mortal Instruments series.