This was a fun new portal fantasy adventure. Two children find a wall blocking their path to school and when they climb over it, they enter the Up-and-Under, a world with giant talking owls, girls that turn into crows, and a road that doesn't stay in place. Avery and Zib are complete opposites but must stick together to find their way home. I enjoyed the tension of their two personalities, esp Avery's rejection of anything that doesn't make sense.