Jack and Annie have to find a certain kind of food, the fourth thing needed to save Merlin's penguin, Penny. The magic tree house whisks them off to a village in the mountains of China, close to a panda reserve. They don't know it, but they've arrived on the day of a historic earthquake! How will they survive when the giant quake strikes? Will they be able to rescue the pandas? And how will they ever get back to the tree house so that they can fulfill...

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

The magic tree house whisks Jack and Annie to India during the Mogul Empire in the 1600s to search for an emerald needed to break a magic spell.

Jack and Annie travel in their Magic Tree House back to a Hawaiian island of long ago where they make friends, learn how to surf, and encounter a tsunami.

Jack and Annie travel back to Victorian London when Merlin asks them to use their magic to inspire Charles Dickens to write "A Christmas Carol."

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 are transported to 1944 Europe, where they parachute behind enemy lines in Normandy, France, to help Allied forces during one of history's darkest moments.

When Merlin is weighed down by sorrows, Jack and Annie travel back to feudal Japan to learn one of the four secrets of happiness.

The magic tree house whisks Jack and Annie to Washington D.C. in the 1860s where they meet Abraham Lincoln and collect a feather that will help break a magic spell.

Jack and Annie travel to Vienna, Austria, in 1762 where they meet the young Wolfgang Amadeus Mozart and his sister and help save the budding genius' life.