"Where did the tree house come from? Before Jack and Annie can find out, the mysterious tree house whisks them to the prehistoric past. Now they have to figure out how to get home. Can they do it before dark ... or will they become a dinosaur's dinner?" -- Amazon.com

The magic tree house takes Jack and Annie to Antarctica to search for the fourth secret of happiness for Merlin.

"The magic tree house has whisked Jack and Annie to ancient Egypt. Inside a pyramid, Jack and Annie find a long-dead queen who needs their help solving a centuries-old riddle. If only they can find their way through the pyramid's maze!"-- Provided by publisher

A castle looms dark against the light of the moon. No candles burn in its windows. No laughter rings through its halls. What has happened to the castle and the people who lived there? Merlin the magician asks Jack and Annie to find out. But are they brave enough to step through the creeking doors and solve the mystery of how the castle became haunted?

Eight-year-old Jack, his seven-year-old sister, Annie, and Peanut the mouse ride in a tree house to the Amazon rain forests, where they encounter giant ants, flesh-eating piranhas, hungry crocodiles, and wild jaguars.

Jack and Annie travel to a monastery in the Swiss Alps where, with the help of St. Bernard dogs and magic, they seek the second of four special objects necessary to break the spell on the wizard Merlin's beloved penguin, Penny.

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.

"Jack and Annie search for the fourth secret of greatness for Merlin the Magician in Mexico City at the 1970 World Cup Games. They hope to learn something new from soccer player great, Pele"-- Provided by publisher.

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.

Guided by a magic rhyme, Jack and Annie travel to ancient Baghdad on a mission to help the Caliph disseminate wisdom to the world.