The fan-favorite chapter-book series sends Jack and Annie back to India over 400 years ago to search for a rare and precious emerald. Once there, they discover an amazing and exotic world filled with great danger. Will they find what they're looking for? Will they avoid the wrath of the all-powerful Great Mogul, survive a crazy ride on a wild elephant, escape an attack by king cobras—and make it back to the magic tree house alive?Mary Pope Osborne brings together just the right combination of history, magic, and fast-paced adventure to satisfy kids, parents, teachers, and librarians all over the world with her New York Times bestselling series.