One summer day in Frog Creek, Pennsylvania, a mysterious tree house appeared in the woods.

Eight-year-old Jack and his seven-year-old sister, Annie, climbed into the tree house.

The tree house was filled with books and it was magic. It could go any place that was in a book. All Jack and Annie had to do was to point to a picture and wish to go there.

They visited dinosaurs, knights, an Egyptian queen, pirates, ninjas, and the Amazon rain forest.

Along the way, they discovered that the tree house belonged to Morgan le Fay. Morgan was a magical librarian from the time of King Arthur. She traveled through time and space, gathering books for her library.

One day, Jack and Annie found a note that said Morgan was under a spell. Jack and Annie set out in the magic tree house to find four special things that would free her.

With the help of a mouse named Peanut, Jack and Annie found the first thing in old Japan, the second in the Amazon rain forest, and the third in the Ice Age.

Now Jack, Annie, and Peanut are ready to find the last thing… in Midnight on the Moon.