In 1836, Sonnyboy Parker sets out to join the Texas army. He's too young, he needs a weapon, and instead of a horse, he has an ornery old donkey named Kate. But Sonnyboy is an orphan, adopted by the Parker family, and this is his chance to earn his own land. Texas soldiers will be granted 640 acres each-if they survive the war. At first Sonny boy resents Kate. She's the ugliest thing he's ever seen. But in the face of danger, Kate shows she's not afraid of anything. And together, they may both become unlikely heroes.