Clary has no choice but to travel to the City of Glass if she must save her mother. She does so knowing that to enter without permission is death. Jace doesn’t like it, and Simon has been imprisoned by the Shadowhunters. Clary begins to dig into her family’s past and crosses paths with a Shadowhunter named Sebastian. She doesn’t have much time, for the diabolical Valentine is mustering the full force of his power for one final assault on the Shadowhunters. Jace needs to discover how much he’s willing to risk for Clary, and Clary will need to control her newfound powers to save the Shadowhunters and their city.