Christmas in Camelot by Mary Pope Osborne (audiobook)-128 pages in print
I really enjoyed reading this series as a kid (though I don't remember which ones I have read), as they take readers to faraway lands in distant times. It would be really fun to go to the places and witness the events that Jack and Annie go to in these novels, especially in a magic tree house. I loved to read as a kid, and still do, and these novels took me to magical lands and helped shape my imagination and curiosity. In this novel, Jack and Annie are invited by an "M" (which turns out to be Merlin and not Morgan) to Camelot for Christmas, where they meet King Arthur for the second time and his Knights of the Roundtable for the first time. They end up going to "The Other World" to save Camelot from black magic at the behest of "The Christmas Knight." It turns out that Merlin was angry at King Arthur for banishing Magic from Camelot and got back at him by using magic to put Camelot in a dark slumber and send for Jack and Annie, hoping that they would volunteer to save Camelot. Jack and Annie are able to save Camelot with Merlin's help. Overall, it was still pretty fun to listen to this, though kids are the target audience.