After being run out of Boneville, the three Bone cousins -- Fone Bone, Phoney Bone, and Smiley Bone -- are separated and lost in a vast, uncharted desert. One by one, they find their way into a deep, forested valley filled with wonderful and terrifying creatures.

Eventually, the cousins are reunited at a farmstead run by tough Gran'ma Ben and her spirited granddaughter, Thorn. But little do the Bones know, there are dark forces conspiring against them and their adventures are only just beginning!