The adventure starts when cousins Fone Bone, Phoney Bone, and Smiley Bone are run out of Boneville and later get separated and lost in the wilderness, meeting monsters and making friends as they attempt to return home.

Fone and Smiley Bone encounter complications in the form of Rock Jaw, an enormous mountain lion, and baby animals orphaned by rat creature attacks as they journey through the wilderness with a lost rat creature cub they are returning to the mountains.

It's full-fledged war as Briar, the rat creatures, and the Pawan army storm the city of Atheia. The Bone cousins, Thorn, and Gran'ma Ben are all there to defend the Valley and stop the return of the Lord of the Locusts. When Thorn goes inside a ghost circle, she hears a voice urging her to seek the Crown of Horns. What follows is another dangerous journey for Thorn and loyal Fone Bone as they race to the sacred grounds of the dragons, searching for...

The war in the valley rages on while the Bones, Gran'ma Ben, and their loyal rat creature cub venture on a dangerous trek to Atheia, the old city of the royal family. The goal is to bring Thorn to safety, but to do so they must first travel through fields of the mysterious ghost circles where reality meets the supernatural -- and all this while fending off deadly attacks from Briar, Kingdok, and the rat creatures.

Little Mouse gets dressed to go to the barn with his mother, brothers, and sisters.