Something strange is happening at the Clarksville City Zoo. Late at night, monkeys are scaling the walls and searching the neighborhood--but what are they looking for?Noah, his sister Megan, and their best friends, Richie and Ella, live next door to the zoo. Megan is the first to notice the puzzling behavior of some of the animals. One day Megan disappears, and her brother and their friends realize it's up to them to find her...