Episode Title: "THE CLOUD MINDERS"
Production Number: 74
Original Air Date: 02-28-69
Stardates: 5818.4, 5819.3
A botanical plague is threatening all vegetation on Merak Two, and the U.S.S. Enterprise heads to another Federation member world, Ardana, the only known source of zenite, which can halt the plague.
When Captain Kirk and Commander Spock beam down to the mine entrance to pick up the needed zenite, they are attacked by a group of disgruntled miners called Troglyte Disrupters. Administrators from Stratos -- a floating city sustained by antigravity high above the surface -- drive off the miners and offer Kirk and Spock their hospitality in the floating city while the needed zenite is found.
The Stratos dwellers claim to be enlightened and logical, and view the Troglyte miners as inferior workers; but Dr. McCoy discovers that gas from zenite ore, which the Troglytes process, causes impaired reason and heightened emotions, and that filter masks would let the Troglytes reason as well as the Stratos dwellers.
Factoid: Vulcans mate on a seven-year cycle.
Alien Races: *Ardanans
KEY: [brackets]=illusions *star=first appearance