Magic Tree House #9: Dolphins at Daybreak by Mary Pope Osborne

The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system!It's sink or swim for Jack and Annie when the Magic Tree House whisks them off to the middle of the ocean. Luckily, they find a mini-submarine on a coral reef. Unluckily, they are about to meet a giant octopus and one very hungry shark. Will the dolphins save the day? Or are Jack and Annie doomed to be dinner?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 booksMerlin Missions: More challenging adventures for the experienced readerSuper Edition: A longer and more dangerous adventureFact Trackers: Nonfiction companions to your favorite Magic Tree House adventuresHave more fun with Jack and Annie at MagicTreeHouse.com!