After the events of The Stone Forest, Hilda and Baba switch species, with Baba turning into a human, and Hilda turning into a troll. Hilda goes on an adventure to find a way to bring herself back human again, with her mother, Johanna, trying to find for her in the mountains. Hilda must find a way to get herself back home as a human, and prevent the citizens of Trolberg from being invaded by trolls.