Kirk returns to a planet he surveyed years ago as a younger officer. There he discovers that the villagers and the hill people are now fighting, because the villagers have developed crude firearms and the idea that they should simply take anything they want from the hill people. Worse, Spock is the victim of a gunshot! Kirk and McCoy return to the surface to investigate more completely, but Enterprise must leave to avoid detection - and then a mugato bites Kirk! He must make contact with the hill people, who number among them a kind of witch doctor called a kanutu, who may be able to help. But that help comes with a price...