This latest entry in Jones' Chrestomanci series posits the surfacing of young witches in the closed, confined world of a traditional (though co-ed) boarding school, in a time after witchcraft has been stamped out but inquisitors are still afoot. A witch's gifts commonly show themselves around age eleven, which is just what happens here--to the terror and discomfort of Charles, who holds his finger to the candle flame to remind himself that "burning hurts"; the temporary joy of fat pariah Nan, who's delighted with her change in status; and the likely enjoyment of readers treated to the boarding-school intrigues and spellbound indiscretions. With the coming out of Nan and Charles, relationships shift, all hell breaks loose, more witches (one of them a teacher) reveal themselves, and when things get too hot the arch-enchanter Chrestomanci shows up, summoned by spell from a parallel world. This dapper gentleman settles in at the school, posing as divisional inquisitor and occasioning more shakeups, some of them quite unwelcome to the witches. There is also much exposition about the many parallel worlds of the series: The one in the story, where witchcraft is common but illegal, seems to be a redundant twin of another (ours?) . . . to which it is joined in the explosive classroom finale. And so the whole business is negated in a pouf of Guy Fawkes smoke--but it's larkish fun while the sparks fly.