Eleven-year-old Mary Tucker dreams of visiting the Amazon. But if her father, a museum curator, has his way, she might be a grandmother before she ever gets the chance. One day, while mischievously exploring the museum's warehouse with her brother Ike and best friend Helen, Mary stumbles across an old travel trunk belonging to her grandfather. Inside, they discover an nondescript glass globe. Curious about the simple object, Mary touches the globe, and is shocked when the room is suddenly consumed by the most amazing view of Earth. The magnificent globe lets the friends zoom closer and closer toward the earth's surface, eventually bringing them close enough to touch the trees. That's when the globe entirely disappears, and they find themselves falling. Suddenly, they're far from home, in place that's either a paradise, or the place where they will die. Sleep, water, and food become precious and scarce. A native tribe may hold the keys to their survival as well as clues to help them get back home. But it won't be easy. The rain forest is a big place, and when others find out what the globe can do, Mary, Ike and Helen will need a plan, allies, and a little luck.