Hilda and the Mountain King takes off from the cliff hanger in Hilda and the Stone Forest that left you waiting breathlessly! We rejoin our heroine for her latest adventure just as she awakes to find herself in the body of a troll! Her mother is worried sick, and is perplexed by the strange creature that seems to have taken Hildas place. Now, both of them are in a race to be reunited before Ahlberg and his safety patrol get the chance to use their new secret weapon to lay waste to the trolls, and Hilda along with them!