What are the motifs in Fog Magic by Julia L. Sauer?

The unknown is a strong idea throughout the story of FOG MAGIC. Even though the protagonist, eleven-year-old Greta, is drawn to the forest and the other side of the mountain by the thick fog, she doesn't know what awaits her. When she detects the dim outline of a house in the forest during a thick blanket of fog, she begins to understand that she is venturing into a world that is unknown to the other people of her village, Little Valley.