The #1 bestselling Magic Tree House series is ready to whisk you away with Jack and Annie! This time, meet famous explorer Leif Erikson and help save a narwhal! When the magic tree house whisks Jack and Annie off to Greenland, they´re not sure what time they´ve landed in, but they immediately know what their mission is: save a narwhal! Then they meet a young hunter named Leif Erikson and they ask for his help. But Leif has other ideas... Track the facts with Jack and Annie in the nonfiction companion to this book: Narwhals and Other Whales.