In the 1950s, in Christchurch, New Zealand, two teenage girls, Pauline and Juliet, form an intensely close friendship. Pauline, a shy and introverted girl, struggles with her strained family life, while Juliet, a charismatic newcomer from England, has a dazzling personality and an imaginative flair. As their bond deepens, they create an elaborate fantasy world called Borovnia, where they escape from their mundane and often troubling realities. Their parents and teachers become increasingly concerned about the intensity of their friendship and the violent and fantastical stories they craft together.

The girls' relationship grows more obsessive, and they begin to resent any attempts to separate them. Their shared delusions and dreams reach a point where the boundaries between their fantasy world and real life blur dangerously. As they plan to escape their restrictive environments, their actions become increasingly erratic and disturbing, leading to a tragic chain of events. The story explores themes of friendship, imagination, and the perilous line between fantasy and reality.