Book three in this fast-paced and exciting series for middle grade fantasy, mystery, and animal buffs. Noah, Megan, Richie, and Ella are the Action Scouts; friends whose tree house overlooks the Clarksville City Zoo. When they discover a magical world hidden within the zoo, they are swept away on an adventure in which penguins can fly, a mysterious figure lurks in the shadows, and the scouts are enlisted to help Mr. Darby,...