Unlikely friends Audrey and Ivy find themselves at the centre of a new mystery when a fellow student disappears in suspicious circumstances. Their only clue is a card left by the enigmatic Magpie Society. With time running out and the police baffled, Audrey and Ivy must delve deeper than ever into the dark secrets that their school is hiding. But someone is playing a deadly game. And to beat them, Audrey and Ivy have to start rewriting the rules.