The #1 bestselling Magic Tree House series is ready to whisk you away across the world with Jack and Annie--this time to rescue little horses in Mongolia!Perfect for chapter book readers. Jack and Annie hear the cry of a golden eagle when the magic tree house spins them back in time to a nature reserve for horses!As Eco-Volunteers, Jack and Annie find themselves alone in Mongolia, on a plain in the middle of the night.Under the light of a full moon, they ride mountain bikes across the land, summon a mysterious helper, and try desperately to save wild horses whose very existence is in danger. Can Jack and Annie protect the last of the little horses?Did you know that there's a Magic Tree House book for every kid?Magic Tree House: Perfect for readers who are just beginning chapter booksMerlin Missions: More challenging adventures for the experienced readerFact Trackers: Nonfiction companions to your favorite Magic Tree House adventuresGraphic Novels: Relive the original adventures brought to life with art by Kelly & Nichole Matthews