The Federation sends Kirk to negotiate for mining rights with Aka'ar, Te'er of the Ten Tribes of Capella IV. Capella IV has deposits of the rare mineral topaline, needed for life support systems. The Klingons need this mineral, too, and their presence creates tension further complicated by conflict among the members of the tribe. Ma'ab murders Aka'ar and becomes the new Te'er, and he has a decidedly different attitude that favors the Klingonm perspective. Worse, Kirk and McCoy will not stand by while he murders Ele'en, the pregnant wife of the old Te'er, despite this being Capellan tradition. Soon enough, the Federation party is running for the hills - literally - with Capellans and a Klingon in pursuit.