The Enterprise visits the twin planets of Eminiar VII and Vendikar so Ambassador Fox may approach their governments about joining the Federation. When they beam down to Eminiar 7, Kirk, Spock and the rest of their landing party are informed that the Enterprise has been struck by enemy missiles and Kirk's party, along with the rest of the crew, have been declared casualties. Investigating further, Kirk discovers that the war between the two planets is controlled by computers, which determine the damage done and the fatalities caused by the attacks, and assigns citizens to report to disintegration machines, which they do willingly. Kirk is trapped on the planet, but Ambassador Fox thinks he can remedy the situation and beams down unarmed against Scotty's advice.
