Aria, the world traveler, travels to China with her dog Daisy to visit her friend Mei-Ling. Together they go sight-seeing in Beijing and find a map dropped by a mysterious man. The map has 3 places marked green and says "Seek 3 emeralds and you will find a treasure!" It leads them to visit the Great Wall of China, Guilin city, and Shanghai. In each place they find a clue. By connecting all three clues together, they find a golden key and a treasure chest! However, a suspicious boy comes to steal the treasure chest. Then the mysterious man who dropped the map suddenly appears and scares the boy away. Who is this mysterious man? Finally, Aria gets to open the treasure chest! This book series not only introduces children to other cultures, but also educates them about geography by having maps of the world, continents, and the country Aria visits.