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

Hilda is starting to shirk her responsibilities, seeking days filled with excitement instead of spending time at home… and her mother is getting worried. While trying to stop Hilda from sneaking out into the house spirits’ realm, the pair find themselves flung far away into a mysterious, dark forest – the land of the trolls! Will they be able to work out their differences in time to rescue each other and get back home? And are the trolls all as sinister as they seem?