Based on the Hildafolk series of graphic novels by Luke Pearson.
Sequel to: Hilda and the hidden people.
"Hilda and her mom have settled into their new home in the city of Trolberg. Pining for her magical friends and the wonder-filled wilderness, Hilda is finding it hard to fit in, especially at school. But when Hilda makes a new friend she soon begins to uncover some surprising secrets ... Perhaps this concrete labyrinth is a place where wonderful and magical things can happen too?" -- (Source of summary not specified).