Beaming down to pick up a consignment of zenite from the planet Ardana, the home of Stratos, a city that floats above the surface of the planet, Kirk and Spock, who are there to pick up a consignment of zenite, are ambushed by mineworkers known as Troglytes. The attack is cut short by the arrival of Plasus, a high advisor from Stratos, who says that a disruptive group of protesting Troglytes probably stole the zenite shipment, which was missing. On Stratos, which Plasus says is safe, there is also evidence of Troglyte terrorism. Kirk and Spock discover that the Stratos dwellers live an easy life thanks to their planet's unique mineral resources at the expense of the Troglytes, who get no reward for extracting those resources.
