Magic Tree House: #12 Polar Bears Past Bedtime by Mary Pope Osborne
From Random House Books for Young Readers:
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 icicle city…when the Magic Tree House whisks Jack and Annie to the frozen Arctic. Luckily, a seal hunter on a dogsled lends them warm clothes. Unluckily, they get stuck on cracking ice. Will the giant polar bear save them? Or will Jack and Annie become frozen dinners?