Four friends - Noah and his sister Megan, Ella and Richie - lived next to the city zoo and had long been accustomed to such a neighborhood. The kids went to school, walked, played in the treehouse... until one day Megan disappeared. Everyone is looking for her: parents, neighbors, police, but the girl disappeared without leaving a trace. Only Noah has the key to the solution: it seems that before her disappearance, her sister saw something... strange. Following mysterious clues, Noah and his friends set out to find Megan. They find themselves in a zoo and realize that this place is actually magical. Friends strive to uncover his secret, safely hidden from prying eyes... A secret that must be kept at all costs! The book is a winner of the American literary award Children's Crown Award, the winners of which are chosen by the readers themselves.