這一次，魔法師梅林要傑克和安妮到一個比卡美拉更古老的時代，去尋找「光明之劍」，他需要這把劍來拯救卡美拉。傑克和安妮再度接受了挑戰！這段旅程裡充滿了傳說中的奇妙怪物：水武士、蜘蛛女王、老灰鬼、海豹人，在泰迪和新朋友凱薩琳的幫助下，他們穿過水母洞到達暴風雪海岸灣，這對小兄妹能在天黑前及時取回光明之劍？他們有辦法回答出大海蛇的古老問題嗎？
　　★本書中譯版《神奇樹屋31：驚天大海怪》由小天下出版。
The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system
Jack and Annie are off on another mythical mission at the request of Merlin the magician. Luckily, they have a young sorcerer, Teddy, to help them. From underwater caves to a Spider Queen, from mystical selkies to a magical sword, this is a Magic Tree House adventure kids won't want to miss
Formerly numbered as Magic Tree House #31, the title of this book is now Magic Tree House Merlin Mission #3: Summer of the Sea Serpent.
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 many novels, picture books, story collections, nonfiction books, and chapter books--including all of the Magic Tree House books, which have been translated into numerous languages around the world. She works with her husband, Will, and her sister, Natalie, on the nonfiction companion series, Magic Tree House Research Guides. Mary lives in Connecticut with Will and their three Norfolk terriers, Joey, Mr. Bezo, and Little Bear. For more information, visit MaryPopeOsborne.com.
SAL MURDOCCA has illustrated over 200 children’s trade and textbooks. He is also a librettist for a 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. He has illustrated all of the Magic Tree House books and all of the Magic Tree House Research Guides. Sal and his wife split their time between New York and France.