Trouble with Gnomes

When Hettie is playing hide and seek with her best friend, she ends up falling down a sinkhole. Little does she know that this actually leads to a secret underground kingdom full of gnomes! The gnomes all bow down to Hettie, thinking she is a great hero who has come to save their home from an army of monsters. But Hettie's just a normal kid... can she really become a hero and save them?