The schoolchildren call it the Ice Palace: a frozen waterfall in the Norwegian fjords transformed into a fantastic structure of translucent walls, sparkling towers and secret chambers. It fascinates two young girls, lonely Unn and lively Siss, who strike up an intense friendship. When Unn decides to explore the Ice Palace alone and doesn't return, Siss must try to cope with the loss of her friend without succumbing to a frozen world of her own making.