Still determined to do all she can to rescue her mother from the enchanted sleeping sickness, Clary uses all her ingenuity and newfound magical powers to get herself into Idris, the forbidden country of the secretive Shadowhunters, and to its capital, the City of Glass, where with the help of newfound friend Sebastian she tries to uncover important truths about her family's past and save not just her mother but all those that she loves.