As the Enterprise approaches planet Omega IV, they find another starship, the U.S.S. Exeter, in orbit. Kirk, Spock and McCoy beam aboard to find the ship abandoned but strewn with uniforms and crystals. The last log entry from the ship's surgeon tells them they have been infected with a deadly virus brought aboard from a returning landing party. Kirk's party beams down to the planet's surface and finds there is one Exeter survivor: Captain Ron Tracey. He has apparently ignored the Prime Directive and has taken sides in a local dispute supporting the Kohms against their arch-rivals, the Yangs. As McCoy tries to find a cure for the virus, Spock and Kirk try to make sense of the situation. They eventually realize there is an odd parallel with Earth's own history. Written by
Did You Know?
Only episode where a victim of the Vulcan neck-pinch actually makes a sound at the time of the pinch. Normally, the neck-pinch incapacitates the victim before he/she can make a sound. See more
During the final scene on the planet, Kirk, Spock, and McCoy are standing together before they leave. During a pause in one of Shatner's lines, Nimoy starts saying something on top of Shatner, then abruptly stops. The camera keeps rolling and you can see Nimoy's eyes roll over as he realizes his mistake. See more
Ay plegli ianectu flaggen, tupep like for stahn...
Captain James T. Kirk
And to the Republic for which it stands, one Nation, under God, indivisible, with Liberty and Justice for all.