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.

If you're looking for Merlin Mission #33: Carnival at Candlelight, it was renumbered as part of the rebrand in 2017 as Merlin Mission #5.