The city of Trolberg has some dark secrets to reveal... and our favourite blue-haired adventurer is about to discover them!

Hilda and her mum have relaxed into city life now, but Hilda is starting to shirk her responsibilities and has enough magical friends and tricky ways that it's easy for her to defy her mother's wishes. After a daring escape attempt, the pair find themselves on the other side of the wall, furious with each other and forced to embark on a dangerous adventure through the land of the trolls...