Students at the Magisterium are supposed to be safe. Under the watchful eyes of the mages, they are taught to use magic to bring order to a chaotic world. But now the chaos is fighting back. Call, Tamara, and Aaron should be worrying about things like pop quizzes and magic contests. Instead, after the shocking death of one of their classmates, they must track down a sinister killer… and risk their own lives in the process. As Call, Tamara, and Aaron discover, magic can only be as good as the person who wields it. In evil hands, it has the capacity to do immeasurable harm, unless it is stopped in time. In this striking third book of Magisterium, bestselling authors Holly Black and Cassandra Clare present us with a school where anything, good or evil, can happen, and the only way to unlock the truth is to risk everything to find it.