The Magic Tree House is a series of children's books written by American author Mary Pope Osborne. The series consists of two groups. The first group consists of books 1-28, in which Morgan Le Fay sends Jack and Annie, two normal children from Frog Creek, Pennsylvania, on numerous adventures and missions with a magical tree house in order to help free Morgan from a spell, solve four ancient riddles to become Master Librarians, and save four ancient stories from being lost forever. The second group, referred to as the Magic Tree House "Merlin Missions," begins with book 29, Christmas in Camelot. In the Merlin Missions, Jack and Annie have quests from the ancient wizard Merlin the Magician. These books are longer than the previous 28, and some take place in fantasy realms like Camelot. Kathl