為傑克和安妮受邀前往卡美拉過耶誕節，但是，遭到黑暗巫師的詛咒，卡美拉陷入悲傷與寂寞之中，歡樂不再。亞瑟王派出了最勇敢的圓桌武士前往異世界，然而卻一去不回。為了拯救卡美拉，這對小兄妹自告奮勇去尋找「記憶與想像之水」，在這個充滿魔法與怪物的幻想世界裡，他們該如何用智慧與勇氣化解危機？並且救回消失的圓桌武士，讓卡美拉不會永遠被人們遺忘呢？
　　The Magic Tree House series has become a staple for inspiring kids to read. Christmas in Camelot is a very special Magic Tree House book. Here, author Mary Pope Osborne uses the literary skills for which she’s known to create a longer, more in-depth story featuring the characters kids have come to love. The result is magical: a fast-paced but detailed, easy-to-read story. Jack and Annie go on a quest to save Camelot, a quest that will prove to a beleaguered King Arthur that children and imagination really can make a difference.
　　★本書中譯版《神奇樹屋29：消失的圓桌武士》由小天下出版。
作者簡介
瑪麗‧奧斯本（Mary Pope Osborne）
　　美國知名兒童文學作家，北卡羅萊納大學主修戲劇與比較宗教學，喜愛不同文化的她，畢業之後，曾到世界各地去旅行。寫作至今已20餘年，作品超過50本以上，並獲得許多獎項，而且擔任過兩屆的美國作家協會主席。
　　MARY POPE OSBORNE is the author of the New York Times number one bestselling Magic Tree House series. She and her husband, writer Will Osborne (author of Magic Tree House: The Musical), live in northwestern Connecticut with their three dogs. Ms. Osborne is also the coauthor of the companion Magic Tree House Fact Trackers series with Will, and with her sister, Natalie Pope Boyce.