MirrorMask centers on Helena, a 15 year old girl in a family of circus entertainers, who often wishes she could run off and join real life. After a fight with her parents about her future plans, her mother falls quite ill and Helena is convinced that it is all her fault. On the eve of her mother' s major surgery, she dreams that she is in a strange world with two opposing queens, bizarre creatures, and masked inhabitants. All is not well in this new world - the white queen has fallen ill and can only be restored by the MirrorMask, and it' s up to Helena to find it. But as her adventures continue, she begins to wonder whether she' s in a dream, or something far more sinister.