One summer day in Frog Creek, Pennsylvania, a mysterious tree house appeared in the woods. It was filled with books. A boy named Jack and his sister, Annie, found the tree house and soon discovered that it was magic. They could go to any time and place in history just by pointing to a picture in one of the books. While they were gone, no time at all passed back in Frog Creek.

Jack and Annie eventually found out that the tree house belonged to Morgan le Fay, a magical librarian from the legendary realm of Camelot. They have since traveled on many adventures in the magic tree house and completed many missions for both Morgan le Fay and her friend Merlin the magician. Teddy and Kathleen, two young enchanters from Camelot, have sometimes helped Jack and Annie in both big and small ways.

Now Jack and Annie are about to receive an unexpected call for help.…