Brance Brenneman is used to harsh conditions -- the eldest son of a stern Amish preacher, Brance was bit by a werecat as a young boy, and managed to keep his secret from his family until he was old enough to leave them and their religion behind. Years later, when the nation is divided by the American Civil War, Brance finds himself enlisted in the Union army. By sheer chance, he meets Caleb Chilson, a Confederate soldier who bears his same shapeshifting burden.

Together they leave the war behind to forge a new life in the wilderness of Pennsylvania. But trappers near their camp are hunting bobcats, and they don't much care if Brance and Caleb are only in the fur part of the time. Brance finds his peaceful existence shattered, and he has to fight to defend the life -- and the bobcat, the man -- he's come to love.