Lilith, the horrible, murderous demon, is gone and Jace is alive and well. He and Clary are excited to begin their lives together. But something has gone terribly wrong. Sebastian has kidnapped Jace but the Clave and Clary cannot locate them. When Clary finally finds them, she realizes that the situation is much, much worse than she and the Clave imagined. Sebastian has bounded himself to Jace and now Jace is under Sebastian's complete control. The Clave wants to destroy the evil Sebastian before he summons Lilith and other demons to earth and annihilates the Shadowhunters; however, if they kill him, Jace will also be killed. For the Clave it is an open and shut case, but for Clary and Jace's family it is not easy to give up Jace. Now they must find a way to destroy Sebastian without harming Jace before the Clave finds them. City of Lost Souls is the fifth book in the Mortal Instruments series and it continues to thrill and entertain.