In this sixth adventure of the Magic Tree House series, Jack and Annie are whisked away to the Amazon rainforest in search of the second item needed to break a spell on Morgan le Fay. Armed only with a research book, the siblings navigate the dense, steaming jungle filled with dangerous creatures—crazy ants, hungry piranhas, and a mysterious jaguar. When they encounter a playful monkey who seems to be following them, they must learn to interpret its strange behavior. With help from unexpected friends, including a gentle sloth, Jack and Annie overcome their fears and discover that the rainforest holds wonders beyond imagination.