Cammie Morgan always knew that becoming a Gallagher Girl would mean a life of risk, pressure and danger beyond her wildest dreams. She just never thought all those things would start during her junior year of high school. It s been two months since Cammie listened as her mother explained that, for unknown reasons, a two-hundred-year-old terrorist organisation, the Circle of Cavan, had Cammie in their sights. To get away from the danger she s in, Cammie takes a trip to London with her friend Bex.There she is relieved to see Joe Solomon, her favourite teacher and her mother s most valued friend, on a London street. However, before he can speak to her, he is nearly arrested by the CIA and MI-6, who suspect him of being a double agent and a leading conspirator in the kidnapping attempts of last semester. Before he escapes, he utters a cryptic warning to Cammie, which leads her to suspect that her beloved school, Gallagher Academy, may no longer be safe. Cammie and her roommates must now call upon old friends and venture to new places while they try to determine what the Circle of Cavan wants with Cammie, and try to discover the identity of the real traitor at the Gallagher Academy before it s too late…