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 arrive on the one continent they havent visited before: Antarctica! What can they hope to learn about happiness in such a barren place? Only the penguins know for sureJack and Annie are about to find out!

Formerly numbered as Magic Tree House #40, the title of this book is now Magic Tree House Merlin Mission #12:Eve of the Emperor Penguin.