Onepenny is exactly the kind of horse Nathan has dreamed of owning - smart, loyal and easy to handle. What's more, this unusual horse with the spotted rump can do tricks. So, Nathan works out a trade with Onepenny's owner, Temple Cholach, and to his delight, the spotted horse becomes his. Before he can even show his parents his new horse, Nathan encounters a posse looking for a stagecoach robber who had ridden a spotted horse. It seems that Temple Cholach isn't the drifter he claimed to be. And when Nathan discovers that Onepenny can lead him to Cholach's home, he must ask himself, what will he do if he actually finds the outlaw? He soon must answer that question.