Just before the summer vacation 15-year-old Mia and her parents move to the suburbs of Zürich. She has long felt estranged from her parents, and when she asks whether she might be adopted her mother becomes offended – but doesn’t reply. While Mia plunges into a wild teenager existence in an attempt to cope with it all, her body begins to change oddly. First hardly noticeably, but then with a force that threatens to drive her out of her mind. In her despair she attempts to numb herself with sex and drugs, hoping to halt the tidal wave that is overwhelming her. But nature is more powerful. Mia’s transformation progresses inexorably, and she turns into the being which has slumbered within her for years… and is now gaining the upper hand.