Onepenny is the kind of horse Nathan always wanted. He's smart, loyal and easy to handle. Plus, this unusual horse with the spotted rump can do tricks. So Nathan is delighted when he makes a trade with Onepenny's owner. But soon after, Nathan encounters a posse looking for a stagecoach robber who had ridden a spotted horse. Seems the former owner wasn't the drifter he claimed to be. And when Nathan discovers Onepenny can lead him to the outlaw's home, he wonders what he'll do if he faces him again.