After moving with her family from London to Devon, Justine Merrison notices that her daughter Ellen is growing increasingly withdrawn. When probed, Ellen tells Justine that her best friend at her new school, George Donbavand, has been unfairly expelled. But when Justine investigates, she's told by the school's headmistress that she must be mistaken: George Donbavand has not been expelled, because there has never been a boy with that name at the school. Ellen insists that George is real, but the teachers suddenly appear very nervous - as if they're hiding something. And then the phone calls start. Someone keeps ringing Justine demanding that she stop trying to scare and intimidate them. But what's even stranger is that the mystery caller addresses Justine as 'Sandie', which is not and has never been her name ...