Bone #2: The Great Cow Race by Jeff Smith

Fone Bone and his cousins plan to return home after visiting the village of Barrelhaven with Thorn and Gran'ma Ben. But Phoney risks everything on one last get-rich-quick scheme for the town's annual Great Cow Race. As usual, Phoney's plans go disastrously awry, and Boneville seems further away than ever. Meanwhile, ominous signs indicate that a war is brewing, and Fone finds himself helping his friends defend their valley from a formidable enemy.