In this third installment in the series, another semester at Bloor Academy is about to begin, and, as usual, chaos ensues. At home, Charlie's Uncle Paton disappears, then returns ill and powerless. Charlie's friend Benjamin heads off to Hong Kong, and his grandmother Maisie leaves to take care of her sick sister. At the same time, a new and sinister student named Belle arrives and quickly establishes herself as a force to be reckoned with. A new art teacher has joined the staff to find his younger brother, Ollie Sparks, turned invisible by a blue boa (snake, though there are feathers involved) controlled by the evil Ezekiel Bloor. Charlie and his friends try to come up with ways to help Ollie and Billy Raven, the poor orphan being manipulated and tormented by the Bloor clan. One of the strengths of this story (and the whole series) is the way both regular people and those who are magically endowed work toward common goals. A weakness is the lack of progress toward identifying and rescuing Charlie's father, who is barely mentioned in this outing.