In Brighton, a town on the coastal channel, this fifteen-year old divides her time between drawing and a juggling act in her parents’ circus. In total adolescent turmoil, Helena wants only one thing: to get away and finally get involved in what she calls «real life». She finds the circus world, with its masks, make-up and artificiality, quite suffocating until one day her mother, after feeling unwell, is taken to hospital as an emergency case; the circus performances are stopped and Helena finds herself at her grandmother’s, waiting for the doctor’s diagnosis. The night of her mother’s operation, the teenage girl thinks she’s just woken from a nightmare but in fact finds herself in a fantastic world, peopled with giants, talking chickens and dangerous sphinxes. She soon realises that her only hope of salvation lies in finding the «MirrorMask», an object with extraordinary powers, that can bring her back to reality, and so she sets off in search of it.