發射大砲!當神奇樹屋將傑克與安妮帶到美國的內戰時期時，兄妹倆聽到了轟隆作響的大砲聲。他們在那裡遇到一位知名的護士－Clara Barton，並且盡了最大的力量幫助了一些受傷的士兵。這是傑克與安妮所面臨的一段最艱辛，以及和自己生活有極端差異的一次旅程。想知道為什麼會這樣嗎?在第二十一集的故事中真相即將大白。

傑克和安妮有了新的挑戰，為了拯救亞瑟王的王國--卡美拉，他們必須為摩根的圖書館找到四份特別的文件。他們即將出發，去尋找第一樣特別的文件……
神奇樹屋帶著傑克和安妮來到美國南北戰爭的戰場上，在那裡，他們遇到了歷史上知名的護士--克萊拉．巴頓，並且幫助她照料受傷的士兵們。傑克和安妮會捲入這場戰爭嗎？面對殘酷的戰爭和苦難的景象，又會帶給這對小兄妹什麼樣的衝擊與體會呢？
The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system
Cannon fire That's what Jack and Annie hear when the Magic Tree House whisks them back to the time of the American Civil War. There they meet a famous nurse named Clara Barton and do their best to help wounded soldiers. It is their hardest journey in time yet--and the one that will make the most difference to their own lives
Did you know that there's a Magic Tree House book for every kid?

Magic Tree House: Adventures with Jack and Annie, perfect for readers who are just beginning chapter books Merlin Missions: More challenging adventures for the experienced reader Super Edition: A longer and more dangerous adventure Fact Trackers: Nonfiction companions to your favorite Magic Tree House adventures
Have more fun with Jack and Annie at MagicTreeHouse.com

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55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.
SAL MURDOCCA has illustrated more than 200 children’s trade and text books. He is also a librettist for children’s opera, a video artist, an avid runner, hiker, and bicyclist, and a teacher of children’s illustration at the Parsons School of Design. Sal lives and works in New York with his wife, Nancy.