Jack and Annie travel back to nineteenth-century Ireland to inspire a young Augusta Gregory to share her love of Irish legends and folktales with the world.
Jack and Annie wonder when the Magic Tree House whisks them to the Wild West. But before they can say "Boo!" they rush headlong into an adventure filled with horse thieves, a lost colt, rattlesnakes, and a cowboy named Slim.
When nine-year-old Patrick visits his grandparents in Maine, he finds a surprise, his own tree house, but he soon has to find a way to deal with two troubled boys who have taken it over.
Jack and Annie continue to try helping Merlin the magician by searching for the secrets of happiness, and their magic tree house takes them to Antarctica, a wasteland where the penguins may know what to do.
On Christmas Eve, Jack and Annie's tree house transports them to King Arthur's castle at Camelot, where they undertake a quest to the castle of the Otherworld.
While on a mission to prove to Merlin that they can use magic wisely, Jack and Annie travel to seventeenth-century Venice, Italy, to save the city from disaster.
Their magic tree house takes Annie and Jack to Pompeii just as Vesuvius is about to erupt, and they must find a Roman scroll before everything is covered with burning ash.
