When Alexander Cold's mother falls ill, the fifteen-year-old is sent to stay with his eccentric grandmother in New York. A tough and prickly magazine reporter, Kate Cold takes Alex along with her on an expedition to the Amazon to verify the existence of the fierce, gigantic, legendary creature known as the Beast. Joining them on their adventure are a celebrated anthropologist; a local guide and his daughter, Nadia; a doctor; and a local entrepreneur....

While spending the summer in the Amazon rain forest of Brazil doing botanical research, thirteen-year-old Grady discovers a secret language used by the trees to communicate with each other and falls afoul of the dictatorial Dr. Carter, whose motives seem questionable.