A child and her family journey into a mountain's deepest caves in this awe-inspiring nonfiction picture book from Sibert Honoree and author of Jumper, Jessica Lanan -- perfect for fans of Jason Chin's Grand Canyon and Caldecott Honor book Wonder Walkers.

Deep, deep, deep in the heart of a mountain, a young girl must navigate her way through twists and turns, narrow passageways and huge caverns, with only a light on her head and her wits about her.

She's looking for the Crystal Room -- a hidden treasure trove of naturally formed crystals that is hiding deep within the cave. The journey there is dangerous. But with the right guide, and a little bravery, it will be well worth the adventure.

Award-winning author and illustrator Jessica Lanan takes readers on an epic caving expedition in this stunning nonfiction picture book about the natural wonders hiding beneath the earth's surface.